@article {pmid40287521,
year = {2025},
author = {Kunal, and Dhiman, SK},
title = {An experimental study on effect of curvatures of upstream tube on thermal performance of downstream tube in cross-flow of air.},
journal = {Scientific reports},
volume = {15},
number = {1},
pages = {14669},
pmid = {40287521},
issn = {2045-2322},
abstract = {Heat transfer on a straight tube in the wake of a tube of same diameter with different curvatures was investigated in cross-flow of air at Reynolds number of 35,000. The straight tube was given constant heat flux condition and placed at different spacing ratios of 2.0, 2.25, 2.5, 3.0, 3.5, and 4.0, from the curved tubes at blockage ratio of 0.1. Four different curvatures ratios 0.5, 1.0, 1.5 and 2.0, on curved tubes were given which were aligned with the mainstream as concave and convex profiles forming different combinations of curvature ratios and spacing ratios to analyse their thermal performance. The study shows a paramount advantage of enhanced thermal performance using curved tube combinations over straight tube combinations and identifies a Reynolds number-based inflection point describing "Heat Promoter" as upstream segment of the tube. The results illustrate that concave curved combination with curvature ratio 1.0 at spacing ratio 2.5 exhibited highest thermal performance with 2.36 times enhanced heat transfer.},
}

@article {pmid40283266,
year = {2025},
author = {Hou, Y and Hu, M and Sun, D and Sun, Y},
title = {Numerical Simulation in Microvessels for the Design of Drug Carriers with the Immersed Boundary-Lattice Boltzmann Method.},
journal = {Micromachines},
volume = {16},
number = {4},
pages = {},
doi = {10.3390/mi16040389},
pmid = {40283266},
issn = {2072-666X},
support = {52301035//National Natural Science Foundation of China/ ; BK20230844//Natural Science Foundation of Jiangsu Province/ ; },
abstract = {This study employs numerical techniques to investigate the motion characteristics of red blood cells (RBCs) and drug carriers (DCs) within microvessels. A coupled model of the lattice Boltzmann method (LBM) and immersed boundary method (IBM) is proposed to investigate the migration of particles in blood flow. The lattice Bhatnagar-Gross-Krook (LBGK) model is utilized to simulate the flow dynamics of blood. While the IBM is employed to simulate the motion of particles, using a membrane model based on the finite element method. The present model was validated and demonstrated good agreements with previous theoretical and numerical results. Our study mainly examines the impact of the Reynolds number, DC size, and stiffness. Results suggest that these factors would influence particles' equilibrium regions, motion stability and interactions between RBCs and DCs. Within a certain range, under a higher Reynolds number, the motion of DCs remains stable and DCs can swiftly attain their equilibrium states. DCs with smaller sizes and softer stiffness demonstrate a relatively stable motion state and their interactions with RBCs are weakened. The findings would offer novel perspectives on drug transport mechanisms and the impact of drug release, providing valuable guidance for the design of DCs.},
}

@article {pmid40281346,
year = {2025},
author = {Ali, N and Sajid, M},
title = {Inertial swimming in an Oldroyd-B fluid.},
journal = {The European physical journal. E, Soft matter},
volume = {48},
number = {4-5},
pages = {19},
pmid = {40281346},
issn = {1292-895X},
abstract = {The effects of fluid inertia on a self-propelling inextensible waving sheet in an Oldroyd-B fluid are examined. The swimming velocity of the sheet is calculated in the limit in which the amplitude of the waves propagating along the sheet is small relative to the wavelength of the waves. The rate of work done by the sheet is also calculated. It is found that the swimming speed decreases monotonically approaching a limiting value with increasing Reynolds number (R) for a Newtonian fluid. For an Oldroyd-B fluid, the swimming speed increases to a maximum and then decreases asymptotically to a limiting value with increasing R. In contrast, it increases monotonically to a limiting value with increasing R for a Maxwell fluid. The limiting value is highest for the Maxwell fluid and lowest for the Oldroyd-B fluid. The corresponding value for the Newtonian fluid lies in between. The rate of work done by the sheet increases with increasing Reynolds number for all Deborah numbers. However, the energy consumed at a fixed swimming speed is lesser for an Oldroyd-B fluid than that of a Newtonian fluid. These results suggest that contrary to the Newtonian case, the fluid inertia supports the swimming sheet motion in a complex fluid. At a particular Deborah number, the oscillation frequency of the sheet could be adjusted to achieve the maximum speed. Similarly, at a particular frequency of oscillation, the Deborah numbers could be adjusted to achieve the maximum speed. These observations are in sharp contrast with the previous results reported for Newtonian and second-order fluids.},
}

@article {pmid40276589,
year = {2025},
author = {Suzuki, K and Nakane, D and Mizutani, M and Nishizaka, T},
title = {Gliding direction of Mycoplasma mobile correlates with the curved configuration of its cell shape.},
journal = {Biophysics and physicobiology},
volume = {22},
number = {1},
pages = {e220006},
pmid = {40276589},
issn = {2189-4779},
abstract = {The gliding motility of bacteria is not linear but somehow exhibits a curved trajectory. This general observation is explained by the helical structure of protein tracks (Nakane et al., 2013) or the asymmetric array of gliding machineries (Morio et al., 2016), but these interpretations have not been directly examined. Here, we introduced a simple assumption: the gliding trajectory of M. mobile is guided by the cell shape. To test this idea, the intensity profile of a bacterium, Mycoplasma mobile, was analyzed and reconstructed at the single-cell level from images captured under a highly stable dark-field microscope, which minimized the mechanical drift and noise during sequential image recording. The raw image with the size of ~1 μm, which is about four times larger than the diffraction limit of visible light, was successfully fitted by double Gaussians to quantitatively determine the curved configuration of its shape. By comparing the shape and curvature of a gliding motility, we found that the protruded portion of M. mobile correlated with, or possibly guided, its gliding direction. Considering the balance between decomposed gliding force and torque as a drag, a simple and general model that explains the curved trajectory of biomolecules under a low Reynolds number is proposed.},
}

@article {pmid40274926,
year = {2025},
author = {Dey, R and Patni, HK and Anand, S},
title = {Improved aerosol deposition predictions in human upper respiratory tract using coupled mesh phantom-based computational model.},
journal = {Scientific reports},
volume = {15},
number = {1},
pages = {14260},
pmid = {40274926},
issn = {2045-2322},
abstract = {Aerosol deposition in the human respiratory tract significantly impacts drug delivery, pollutant exposure, and radiological protection. While existing models, such as the Multiple-Path Particle Dosimetry (MPPD) and the Human Respiratory Tract Model (HRTM) from International Commission on Radiological Protection (ICRP) provide valuable insights, their reliance on simplified geometries and flow dynamics, limits their ability to accurately predict particle deposition within realistic anatomies. This study integrates Mesh-type Reference Computational Phantoms (MRCPs) with computational fluid-particle dynamics (CFPD) to address these limitations. Our simulations reveal the influence of complex anatomical features, including nasal cavity, trachea, and bronchial regions, on aerosol deposition patterns. For ambient aerosol particles in the diffusion-dominated regime (< 0.5 μm), CFPD results reveal enhanced nasal deposition fractions than ICRP predictions, while, above this size, the ICRP semi-empirical model shows overestimations. In the extrathoracic (ET) airways, deposition distribution varied significantly between ET1 and ET2, with ET2 receiving 65-75% of deposits (near the junction of ET1 and ET2) under certain flow conditions. In the bronchial bifurcation (BB1), deposition efficiency varies with Stokes number and Reynolds number, revealing localized preferential deposition. These findings enhance our understanding of aerosol behaviour and paves the way for more accurate therapeutic and safety models in radiological protection.},
}

@article {pmid40274905,
year = {2025},
author = {Boudet, JF and Bergmann, M and Iollo, A and Kellay, H},
title = {Effects of boundaries for high Reynolds number artificial swimmers.},
journal = {Scientific reports},
volume = {15},
number = {1},
pages = {14264},
pmid = {40274905},
issn = {2045-2322},
support = {ANR-22-CE06-0007-02.//Agence Nationale de la Recherche/ ; ANR-22-CE06-0007-02.//Agence Nationale de la Recherche/ ; },
abstract = {The spatial organization of active particles or swimmers may depend strongly on the nature of the interaction between the particles and the boundary. Here we use robotic fish of several centimeters dimensions that swim at high enough velocities to reach Reynolds numbers Re of order [Formula: see text] or [Formula: see text]. Under confinement in circular arenas filled with a shallow layer of water, these robots swim mostly near the walls and undergo a gradual transition from swirling motion near the boundaries to large cluster formation as the number of particles in the assembly is increased. This transition is highly dependent on the nature of the walls: for solid impermeable walls this transition occurs for small numbers of fish robots. For porous walls this transition is delayed and occurs at larger numbers. The main reason why the two boundaries affect the swimming differently is the alignment of the fish robots at the wall: for the impermeable boundary the fish robots align with a smaller angle to the wall while for the porous case, the fish robots align with a larger angle at the wall allowing the formation of linear clusters. We carry out numerical simulations of model fish in three dimensions to examine how such experimental results can be understood. The interest of these simulations is that they provide a direct and quantitative view of the properties of the flow engendered by the fish like objects. The interaction of this flow with other fish or with the boundaries is the crucial aspect behind the self organization. These simulations reproduce the main features of the behavior of the swimmers such as their swimming near the walls or their angle with respect to the boundary. By using flexible and free to move arenas in experiments and simulations, we show that the assembly of fish robots is capable of creating large deformations as well as induce mobility of the arenas through the self-organization of the robotic fish opening the possibility of making sub-aquatic flexible robots of robots.},
}

@article {pmid40273102,
year = {2025},
author = {Chen, X and Sreenivasan, KR},
title = {Bounded dissipation law and profiles of turbulent velocity moments in wall flows.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {122},
number = {17},
pages = {e2502265122},
doi = {10.1073/pnas.2502265122},
pmid = {40273102},
issn = {1091-6490},
support = {92252201 12072012//National Science Foundation of China/ ; None//NYU | Tandon School of Engineering, New York University (Tandon)/ ; },
abstract = {Understanding the effects of solid boundaries on turbulent fluctuations remains a long-standing challenge. Available data on mean-square fluctuations in these flows show apparent contradiction with classical scaling. We had earlier proposed an alternative model based on the principle of bounded dissipation. Despite its putative success, a conclusive outcome requires much higher Reynolds numbers than are available at present, or can be expected to be available in the near future. However, the model can be validated satisfactorily even within the Reynolds number range already available by considering high-order moments and their distributions in the wall-normal direction. Expressions for high-order moments of streamwise velocity fluctuation [Formula: see text] are derived in the form [Formula: see text], where the superscript [Formula: see text] indicates the wall unit normalization, and brackets stand for averages over time and the homogeneous plane normal to the wall, [Formula: see text] is an integer, [Formula: see text] and [Formula: see text] are constants independent of the friction Reynolds number [Formula: see text], and [Formula: see text] is the distance away from the wall, normalized by the flow thickness [Formula: see text]. In particular, [Formula: see text] according to the "linear q-norm Gaussian" process, where [Formula: see text] and [Formula: see text] are flow-independent constants. Excellent agreement is found between this formula and the available data in boundary layers, pipes, and channels for [Formula: see text]. For fixed [Formula: see text], the present formulation leads to the bounded state [Formula: see text] as [Formula: see text]. This work demonstrates the success of the present model in describing the behavior of fluctuations in wall flows.},
}

@article {pmid40269237,
year = {2025},
author = {Bhattacharyya, S and Vishwakarma, DK},
title = {Mixed and forced convection heat transfer and pressure drop in inclined tube with twisted tape in transition flow.},
journal = {Scientific reports},
volume = {15},
number = {1},
pages = {14018},
pmid = {40269237},
issn = {2045-2322},
abstract = {Understanding the influence of angular orientation on mixed convection heat transfer and pressure drop in circular tubes with swirl generators is crucial for optimizing thermal performance in various engineering applications, including heat exchangers and energy systems. This study aims to investigate the impact of angular orientation on heat transfer enhancement and pressure drop characteristics in a uniformly heated circular tube equipped with a twisted-tape longitudinal swirl generator. An experimental approach was employed, varying key parameters such as Reynolds number (435-10,130), heat flux (2, 3, and 4 kW/m[2]), twist ratio (P/D = 3, 4, and 5), and angular orientation (15° and 30°). The setup was validated against established correlations for Nusselt number and friction factor, demonstrating strong agreement. The results reveal that angular orientation significantly affects heat transfer and pressure drop at Reynolds numbers up to ~ 1000, where mixed convection plays a dominant role. Beyond this, forced convection prevails. In a plain channel, the transition from laminar to transitional flow occurs at Reynolds numbers of 2924-4088 for a 15° angle of inclination (AoI) and 3001-4274 for a 30° AoI, with the transition occurring slightly earlier at the lower angle. The Richardson number varied from 2.5 in the low laminar regime to 0.0087 in the turbulent regime, with additional variations observed when turbulators were introduced.},
}

@article {pmid40269048,
year = {2025},
author = {Kaziz, S and Echouchene, F and Gazzah, MH},
title = {Optimizing microfluidic chip for rapid SARS-CoV-2 detection using Taguchi method and artificial neural network PSO.},
journal = {Scientific reports},
volume = {15},
number = {1},
pages = {14052},
pmid = {40269048},
issn = {2045-2322},
mesh = {*Neural Networks, Computer ; *SARS-CoV-2/isolation & purification ; *COVID-19/diagnosis/virology ; Humans ; *Biosensing Techniques/methods/instrumentation ; *Lab-On-A-Chip Devices ; },
abstract = {Microfluidic biosensors offer a promising solution for real-time analysis of coronaviruses with minimal sample volumes. This study optimizes a biochip for the rapid detection of SARS-CoV-2 using the Taguchi orthogonal table L9(3[4]), which comprises nine groups of experiments varying four key parameters: Reynolds number (Re), Damköhler number (Da), Schmidt number (Sc), and the dimensionless position of the reaction surface (X). Signal-to-noise (S/N) ratios and analysis of variance (ANOVA) are employed to determine optimal parameters and assess their impact on binding kinetics and response time of the detection device. These obtained optimal parameters correspond to Re = 4.10[-2], Da = 1000, Sc = 10[5], and X = 1. Additionally, results highlight Da as the most influential factor, accounting for 91%, while X has a minimal effect of 0.3%. Furthermore, an artificial neural network optimization technique, specifically particle swarm optimization (PSO), was utilized to predict biosensor performance. Derived from the Full L81(3[4]) design experiment, the PSO model demonstrates its effectiveness compared to the conventional multi-layer perception (MLP) model, thus underlining its potential in this innovative optimization context.},
}

*Neural Networks, Computer
*SARS-CoV-2/isolation & purification
*COVID-19/diagnosis/virology
Humans
*Biosensing Techniques/methods/instrumentation
*Lab-On-A-Chip Devices

@article {pmid40262639,
year = {2025},
author = {Yaqoob, B and Porfiri, M and Pugno, NM},
title = {Optimizing energetics of lateral undulatory locomotion: unveiling morphological adaptations in different environments.},
journal = {Journal of the Royal Society, Interface},
volume = {22},
number = {225},
pages = {20240440},
doi = {10.1098/rsif.2024.0440},
pmid = {40262639},
issn = {1742-5662},
support = {//Italian Ministry of Education, University and Research (MIUR)/ ; //National Science Foundation/ ; },
abstract = {Ongoing efforts seek to unravel theories that can make simple, quantitative and reasonably accurate predictions of the morphological adaptive changes that arise with the size variation. Yet, relatively scant attention has been directed towards lateral undulatory locomotion. In the current study, we explore: (i) the constraints imposed by the variation of length and mass in viscous and dry friction environments on the cost of transport (COT) of lateral undulatory locomotion and (ii) the role of the body, environment and input oscillations in such an intricate interplay. In a dry friction environment, minimum COT correlates with stiffer and longer bodies, higher frictional anisotropy and angular amplitudes greater than approximately 10[o]. Conversely, a viscous environment favours flexible long bodies, higher frictional anisotropy and angular amplitudes lower than approximately 30[o]. In both environments, optimizing mass and maintaining low angular frequencies minimizes COT. Our conclusions are applicable only in the low-Reynolds-number regime, and it is essential to consider the interdependence of parameters when applying the generalized results. Our findings highlight musculoskeletal and biomechanical adaptations that animals may use to mitigate the consequences of size variation and to meet the energetic demands of lateral undulatory locomotion. These insights enhance foundational biomechanics knowledge while offering practical applications in robotics and ecology.},
}

@article {pmid40256679,
year = {2025},
author = {Shankaran, A and Hearst, RJ},
title = {Simultaneous measurements of velocity, oxygen concentration, and deformed interface position in an air-water channel using PIV and LIF.},
journal = {Experiments in fluids},
volume = {66},
number = {5},
pages = {95},
pmid = {40256679},
issn = {0723-4864},
abstract = {Oxygen transfer across a deforming air-water interface is studied using a synergy of particle image velocimetry and laser-induced fluorescence (LIF). Such approaches have previously been limited to flat interfaces. We develop simultaneous measurements of velocity fields, dissolved oxygen (DO) concentration fields, and interface positions for spatial and temporal tracking. The imaging process begins after the DO in the water has been chemically depleted and continues until the water is saturated with DO. The oxygen LIF intensity field is calibrated using measurements from an optical oxygen probe to ensure accurate conversion into physical unit (mg/L). A canonical air turbulent channel flow, with a centerline velocity of 6.6 m/s (Reynolds number based on channel height of 21,700), develops for more than 100 heights before the bottom boundary condition is changed from a solid wall to a water surface. This induces transient and wavy structures on the air-water interface and generates velocity fluctuations and vorticity on the water side, which drives DO transport. The spatial evolution of DO concentration reveals steep gradients near the interface that diminish with depth, while the temporal evolution shows a reduction in concentration differences between the bulk and interface from about 35% to less than 5% as the water saturates. Concentration fluctuations are lower near the interface compared to the bulk and diminish in time as the system approaches saturation. Turbulent scalar transport analysis shows high vertical flux near the interface, and this too changes as the bulk DO concentration evolves, emphasizing that the observed phenomena are transient and should be treated as such.},
}

@article {pmid40250393,
year = {2025},
author = {Wang, Y and Ebrahimi, F and Lu, H and Goodman, J and Gilson, EP and Ji, H},
title = {Observation of Nonaxisymmetric Standard Magnetorotational Instability Induced by a Free-Shear Layer.},
journal = {Physical review letters},
volume = {134},
number = {13},
pages = {135101},
doi = {10.1103/PhysRevLett.134.135101},
pmid = {40250393},
issn = {1079-7114},
abstract = {The standard magnetorotational instability (SMRI) with a magnetic field component parallel to the rotation axis is widely believed to be responsible for the fast accretion in astronomical disks. In conventional base flows with a Keplerian profile or an ideal Couette profile, most studies focus on axisymmetric SMRI, since excitation of nonaxisymmetric SMRI in such flows requires a magnetic Reynolds number (Rm) more than an order of magnitude larger. Here, we report that, in a magnetized Taylor-Couette flow, nonaxisymmetric SMRI with an azimuthal mode number m=1 can be triggered by a free-shear layer in the base flow at Rm≳1, the same threshold as for axisymmetric SMRI. Global linear analysis reveals that the free-shear layer reduces the required Rm, possibly by introducing an extremum in the vorticity of the base flow. Nonlinear simulations validate the results from linear analysis and confirm that a novel instability recently discovered experimentally [Wang et al., Nat. Commun. 13, 4679 (2022)NCAOBW2041-172310.1038/s41467-022-32278-0] is the nonaxisymmetric m=1 SMRI. Our finding has astronomical implications as free-shear layers are ubiquitous in celestial systems, such as the disk-star boundary layer, the solar tachocline, and the edge of planet-opened gaps in protoplanetary disks.},
}

@article {pmid40225806,
year = {2025},
author = {Kavitha, R and Ladu, NSD and Ravi, S},
title = {Soret Effect and Chemical Process on MHD Oscillatory Flow in a Physiological Fluid.},
journal = {Applied bionics and biomechanics},
volume = {2025},
number = {},
pages = {8818822},
pmid = {40225806},
issn = {1176-2322},
abstract = {This paper investigates the impact of chemical and Soret reactions on magnetohydrodynamic (MHD) oscillatory flow in a porous arteriole. Using appropriate mathematical techniques, a model of a mathematical equation is developed and solved. The flow governing equations are formulated based on certain assumptions. Exact solutions are attained for the profiles of velocity, temperature, and concentration. To highlight the key features, the numerical computations of the physical parameters, Grashof number, Reynolds number, Magnetic number, and Soret number were presented graphically. The present study reveals the viscoelasticity of blood significantly reduces flow velocity. And also illustrates blood flow (BF) in the artery is affected by the Lorentz force, which causes the velocity of the BF to increase as the magnetic field parameter values increase. The obtained outcome may be very useful in controlling BF during the surgical procedure.},
}

@article {pmid40224519,
year = {2025},
author = {Jayatilake, S and Lowenberg, M and Woods, BKS and Titurus, B},
title = {Nonlinear aeroelastic modelling and analysis of a geometrically nonlinear wing with combined unsteady sectional and lifting line aerodynamics.},
journal = {Nonlinear dynamics},
volume = {113},
number = {12},
pages = {14657-14693},
pmid = {40224519},
issn = {0924-090X},
abstract = {This research develops a novel geometrically nonlinear aeroelastic model of a cantilevered flexible wing capable of capturing unsteady aerodynamics with finite span effects. The structural model is developed using a Chebyshev-Ritz approach with the ONERA unsteady aerodynamic formulation coupled to a three-dimensional wing analysis based on the lifting line approach. The resulting system describing the evolution of the generalised structural coordinates and the aerodynamic states is formulated as a continuous state space model. The model is validated against experimental results from the wind tunnel testing of a highly flexible wing demonstrator at the University of Bristol. The numerical results are computed by applying a numerical continuation procedure, exercising the benefits of the state space formulation. The extensive numerical-experimental comparative analysis includes the bifurcation characteristics of the system and the behaviour of the aeroelastic modes. The developed model reflected the experimentally identified bifurcation behaviour. The predicted variations of the flutter onset speed with the wing root pitch angles were found to be within 5% of the experimental values. The model also correctly captured the post-flutter Limit Cycle Oscillation (LCO). This work further showed that the predicted flutter speeds are sensitive to the semi-empirical coefficients present in the ONERA unsteady aerodynamics formulation. Consequently, further calibration of the model was based on the analysis of the experimental flutter speeds and airspeed-driven eigenvalue variations. This approach was necessitated by the influence of application-specific conditions (e.g., the Reynolds number) on the unsteady aerodynamic characteristics. Despite this limitation, the tuned model agreed with the experimental observations across a wide range of test conditions. The approaches presented in this work can benefit multiple applications during research on geometrically nonlinear wings, such as the analysis of root causes influencing critical aeroelastic phenomena or design of aeroelastic control laws.},
}

@article {pmid40209649,
year = {2025},
author = {Zhu, F and Hu, X and Wu, X and Xu, D and Li, Q and Chen, X and Pang, W and Duan, X and Wang, Y and He, M},
title = {Synergistic effect of acoustic streaming and nanozymes on enhanced intracellular dopamine detection.},
journal = {Biosensors & bioelectronics},
volume = {280},
number = {},
pages = {117431},
doi = {10.1016/j.bios.2025.117431},
pmid = {40209649},
issn = {1873-4235},
abstract = {Microfluidic electrochemical biosensing has been widely recognized, but it suffers the slow mass transfer caused by low Reynolds number in the microenvironment. This work proposes a multifunctional portable microfluidic electrochemical platform integrated with a gigahertz acoustic resonator, achieving improved electrochemical response, in situ nanozymes modification, cellular pre-treatment and portable detection on one chip. It was observed that the acoustic streaming (AS) generated by the resonator could reduce the thickness of the double electric diffusion layer and improve the mass transfer in bulk solution, leading to an enhancement in microfluidic electrochemical current response. In addition, in situ electrodeposition of polypyrrole (Ppy) and Ni3(HHTP)2 nano-composite nanozymes (Ppy-Ni3(HHTP)2) was achieved to increase the electrocatalytic activity of dopamine (DA). The results further revealed that AS and Ppy-Ni3(HHTP)2 collectively enhance the electrochemical detection of DA. Moreover, cell pre-treatment and intracellular DA detection was achieved to distinguish the passage of dopaminergic cells by the microfluidic electrochemical platform. Finally, portable detection of intracellular dopamine was realized by integrating the platform with the portable electrochemical sensing system. This study presented a novel approach to collectively enhance electrochemical biosensing using AS and nanozymes.},
}

@article {pmid40206413,
year = {2018},
author = {Brindise, MC and Vlachos, PP},
title = {Pulsatile pipe flow transition: Flow waveform effects.},
journal = {Physics of fluids (Woodbury, N.Y. : 1994)},
volume = {30},
number = {1},
pages = {},
pmid = {40206413},
issn = {1070-6631},
abstract = {Although transition is known to exist in various hemodynamic environments, the mechanisms that govern this flow regime and their subsequent effects on biological parameters are not well understood. Previous studies have investigated transition in pulsatile pipe flow using non-physiological sinusoidal waveforms at various Womersley numbers but have produced conflicting results, and multiple input waveform shapes have yet to be explored. In this work, we investigate the effect of the input pulsatile waveform shape on the mechanisms that drive the onset and development of transition using particle image velocimetry, three pulsatile waveforms, and six mean Reynolds numbers. The turbulent kinetic energy budget including dissipation rate, production, and pressure diffusion was computed. The results show that the waveform with a longer deceleration phase duration induced the earliest onset of transition, while the waveform with a longer acceleration period delayed the onset of transition. In accord with the findings of prior studies, for all test cases, turbulence was observed to be produced at the wall and either dissipated or redistributed into the core flow by pressure waves, depending on the mean Reynolds number. Turbulent production increased with increasing temporal velocity gradients until an asymptotic limit was reached. The turbulence dissipation rate was shown to be independent of mean Reynolds number, but a relationship between the temporal gradients of the input velocity waveform and the rate of turbulence dissipation was found. In general, these results demonstrated that the shape of the input pulsatile waveform directly affected the onset and development of transition.},
}

@article {pmid40199959,
year = {2025},
author = {Khan, SH and Danish, M and Ayaz, M and Husain, A and Saeed, S and Abdulla, S and Shaheen, S and Saeed, A and Thaher, A},
title = {Aerodynamic analysis and ANN-based optimization of NACA airfoils for enhanced UAV performance.},
journal = {Scientific reports},
volume = {15},
number = {1},
pages = {11998},
pmid = {40199959},
issn = {2045-2322},
support = {G00004417//Research Office at UAE University/ ; G00004417//Research Office at UAE University/ ; G00004417//Research Office at UAE University/ ; G00004501//College of Graduate Studies, United Arab Emirates University/ ; },
abstract = {The performance of unmanned aerial vehicles (UAVs) is strongly dependent on the design of their airfoils, particularly in applications necessitating high maneuverability, stability, and efficiency. This study analyzed three National Advisory Committee for Aeronautics (NACA) airfoil profiles: NACA 2412, NACA 4415, and NACA 0012, using a combination of computational fluid dynamics (CFD), XFOIL simulations, and a hybrid artificial neural network-genetic algorithm (ANN-GA) model. This study aimed to evaluate and optimize the aerodynamic performance of these airfoils under various flight conditions. Through CFD simulations and XFOIL analysis, we explored the lift, drag, and stall characteristics of each airfoil at different angles of attack and Reynolds numbers. The NACA 4415 airfoil consistently outperformed the others, achieving the highest lift-to-drag ratio ([Formula: see text]) and exhibiting favorable stall behavior. Thus, it is particularly well-suited for UAVs operating in challenging environments. Further, streamline and velocity profile analyses confirmed that NACA 4415 exhibited a smooth airflow and delayed flow separation, thereby contributing to its superior aerodynamic efficiency. Using the hybrid ANN-GA model, we optimized key parameters, such as the angle of attack and Reynolds number with optimal values of [Formula: see text] and 770,801, respectively, for maximum efficiency. Additionally, the ANN model demonstrated a high accuracy in predicting the aerodynamic performance, closely matching the results of the CFD simulations. Overall, this study highlighted the potential of combining computational techniques and machine- learning models to optimize UAV airfoil designs. These findings offer valuable insights for improving the efficiency and agility of UAVs, particularly in industries such as precision agriculture, infrastructure inspection, and environmental monitoring.},
}

@article {pmid40199935,
year = {2025},
author = {Dong, L and Zhang, R},
title = {Numerical study on falling film flow outside the refrigerant tube.},
journal = {Scientific reports},
volume = {15},
number = {1},
pages = {11952},
doi = {10.1038/s41598-025-96057-9},
pmid = {40199935},
issn = {2045-2322},
support = {2023ZR04//Natural Science Foundation of Dongying/ ; 2024ZDJH75//Dongying City Science and Technology Innovation Major Project (Science and Technology Development Guidance Scheme)/ ; DJ2023004//Science Development Funding Program of Dongying of China/ ; },
abstract = {The liquefied natural gas (LNG) floating production storage and offloading (FPSO) unit is a new type of floating production device developed for the exploitation, pretreatment, liquefaction, and storage of offshore natural gas. In this study, the shell side structure of the spiral-wound heat exchanger is analyzed, and the effects of varying the Reynolds number (Re), tube outer diameter, and number of distributors on the thickness of the shell-side liquid film are investigated. The results show that as the fluid flows down from the distributor, it hits the upper wall of the pipeline and diffuses evenly to both sides, before converging in between the two distributors. In the axial direction, the thickness of the liquid film increases first, reaches the highest at the peak, then decreases, reaches the lowest at the trough, and then increases again, forming a secondary peak at the drop. The thickness of the liquid film changes periodically, and the period is the distance between the two distributors. The thickness of the circumferential liquid film is negatively correlated with the circumferential angle, α. Moreover, the liquid film is thinnest at α = 120°, and is positively correlated with both the liquid mass flow rate and the outer diameter of the tube. The most uniform liquid film thickness is obtained when Re = 1500, the tube outer diameter is 12 mm, and the number of distributors is 6. The results from this study can guide the design of spiral-wound heat exchangers and facilitate their safe and efficient operation in natural gas liquefaction processes.},
}

@article {pmid40183380,
year = {2025},
author = {Qin, L and Liu, X and Fei, F},
title = {CFD-Based Optimization of a Dielectrophoretic Device to Isolate CTCs.},
journal = {Electrophoresis},
volume = {},
number = {},
pages = {},
doi = {10.1002/elps.8129},
pmid = {40183380},
issn = {1522-2683},
support = {2024B05//Open Project of Key Laboratory of Education/ ; },
abstract = {Cancer cells that have separated from the main tumor and entered the bloodstream are known as circulating tumor cells (CTCs). Once there, they may spread to other parts of the body and cause metastases. This work proposes a novel inertial-based dielectrophoresis (DEP) device designed for the separation of CTCs from red blood cells (RBCs). The microchannel features a rectangular zigzag segment combined with a circular curved section, optimized to improve separation efficiency by integrating inertial and DEP forces. Numerical simulations are conducted to evaluate the effects of microchannel depth, applied voltage and frequency, and Reynolds number (Re) on the separation efficiency and trajectory of cells. The simulations identify four optimal scenarios that achieve 100% separation efficiency. Early cancer diagnosis and treatment may benefit from the use of the proposed device for CTC detection.},
}

@article {pmid40177117,
year = {2025},
author = {Clemens, AL and Jung, K and Ferrucci, M and Ellis, ME and Davis, JT and Chandrasekaran, S and Qi, Z and Orme, CA and Worsley, MA and Akolkar, R and Ivanovskaya, A and Dudukovic, NA},
title = {Understanding the Current Distribution and Mass Transport Properties in 3D-Printed Architected Flow-Through Electrodes.},
journal = {ACS applied engineering materials},
volume = {3},
number = {3},
pages = {600-612},
doi = {10.1021/acsaenm.4c00561},
pmid = {40177117},
issn = {2771-9545},
abstract = {Architected materials offer promising advancements in energy storage by enabling highly customizable, high-surface-area, ordered, and low-defect porous structures. This study investigates the current distribution and mass transport within complex 3D-printed lattice electrodes under flow-through conditions. Conductive lattices were fabricated using microstereolithography followed by pyrolytic carbonization. Lattice geometry effects were analyzed by varying the unit cell type [simple cubic (SC), body- and face-centered cubic (BCC/FCC), IsoTruss, and Octet], porosity, and current density. Current distribution uniformity was investigated using a model high-efficiency copper deposition reaction. Local film thickness distributions were predicted using a numerical model and validated experimentally using micro-X-ray computed tomography. Scaling relationships for informing electrochemical reaction conditions and current uniformity are formulated as a modified lattice-based Wagner number (Wa Lattice) and a corresponding inverse Damkohler number (Da Lattice [-1]). Validated models reveal that mass-transfer coefficients scale as Octet > IsoTruss > FCC ∼ BCC > SC. Inertial effects become significant at Reynolds number Re > 3 and are particularly pronounced in Octet structures due to an abundance of struts oriented away from the fluid flow direction. The study underscores the importance of electrode engineering and process conditions necessary to tailor mass transport and current uniformities to various device applications.},
}

@article {pmid40167398,
year = {2025},
author = {Zhang, P and Wang, Y and Wang, Y},
title = {Development of pulse-type skin friction balance use in shock tunnel.},
journal = {The Review of scientific instruments},
volume = {96},
number = {4},
pages = {},
doi = {10.1063/5.0246911},
pmid = {40167398},
issn = {1089-7623},
abstract = {The wall shear stress significantly affects the aerodynamic characteristics and flight safety of hypersonic aircraft. More accurate and reliable diagnostic instruments are required to fully understand and optimize the distribution of wall shear stress in hypersonic high-enthalpy flow. Two types of assembled and integrated skin friction balances for high-enthalpy impulse facilities were developed. The integrated balance was processed using additive manufacturing, also known as 3D printing. The static calibration uncertainty of the two types of skin friction balances is lower than 0.2% FS at 95% confidence. The first-order vibration frequency is about 50 Hz. The applicability and reliability of the developed skin friction balance were verified in the JF-12 shock tunnel built by the Institute of Mechanics, Chinese Academy of Sciences. A series of wall shear measurement tests for flat-plate boundary layers were carried out, in a freestream with a nominal Mach number of 7 and a unit Reynolds number of about 106. The wall shear results were in good agreement with the numerical simulation and empirical formula results. The minimum deviation can reach 3.67% of the measured value, which verifies the applicability and reliability of the two types of skin friction balances for accurate wall shear stress in high-enthalpy pulse flow, especially providing experimental support for the feasibility of the additive-manufactured balance.},
}

@article {pmid40160717,
year = {2025},
author = {Turkevich, LA and Chen, H and Jog, MA},
title = {Dust resuspension from the splash of a falling powder: A numerical aerodynamic simulation of a pellet falling onto a powder monolayer.},
journal = {Aerosol science and technology : the journal of the American Association for Aerosol Research},
volume = {59},
number = {1},
pages = {49-65},
doi = {10.1080/02786826.2024.2417976},
pmid = {40160717},
issn = {0278-6826},
abstract = {A falling powder can generate a dust cloud from its interaction with the ambient air and from its splash onto a substrate. This article reports the results of a numerical simulation study, which attempts to model this second process. We argue that the dust cloud arises from the aerodynamic resuspension of previously deposited small particles. The agglomerated falling powder is modeled as a falling pellet disk impacting a surface covered with a monolayer of previously deposited particles. The Reynolds number of the air flow in the vicinity of the impacting pellet is Re ~ 1860, so the air flow is modeled as laminar and incompressible. The dust particles are incorporated via a Lagrangian multiphase treatment. The sudden deceleration of the disk sheds an aerodynamic vortex, which suspends particles from the monolayer. Characteristics of the dust cloud (average and maximum height and radius) are tracked; these are conveniently summarized by following the trajectory of the dust cloud centroid. The probability of aerosolization decreases with distance from the impacted pellet. The centroid trajectory is studied as a function of dust particle size. The model is relatively insensitive to disk radius and thickness. More realistic modeling of dust clouds generated by the splash of falling powders will require a statistical analysis of aggregate size and location, as well as the inclusion of interparticle and particle-surface interactions.},
}

@article {pmid40153508,
year = {2025},
author = {Sui, F and Yue, W and Behrouzi, K and Gao, Y and Mueller, M and Lin, L},
title = {Untethered subcentimeter flying robots.},
journal = {Science advances},
volume = {11},
number = {13},
pages = {eads6858},
doi = {10.1126/sciadv.ads6858},
pmid = {40153508},
issn = {2375-2548},
abstract = {The miniaturization of insect-scale flying robots with untethered flights is extremely challenging as the tradeoff between mass and power becomes problematic. Here, a subcentimeter rotating-wing robot of 21 mg in weight and 9.4 mm in wingspan driven by a single-axis alternating magnetic field has accomplished navigable flights. This artificial flying robot is the lightest and smallest to realize untethered and controllable aerial travels including hovering, collision recovery, and route adjustments. Experimentally, it has achieved a high aerodynamic efficacy with a measured lift-to-drag ratio of 0.7 and lift-to-flying power ratio of 7.2 × 10[-2] N/W at a Reynolds number of ~2500. The wireless driving mechanism, system operation principle, and flight characteristics can be further optimized for the advancement and miniaturization of subcentimeter scale flying robots.},
}

@article {pmid40152021,
year = {2025},
author = {Kuddushi, M and Kanike, C and Xu, BB and Zhang, X},
title = {Recent advances in nanoprecipitation: from mechanistic insights to applications in nanomaterial synthesis.},
journal = {Soft matter},
volume = {},
number = {},
pages = {},
doi = {10.1039/d5sm00006h},
pmid = {40152021},
issn = {1744-6848},
abstract = {Nanoprecipitation is a versatile, low-energy technique for synthesizing nanomaterials through controlled precipitation, enabling precise tuning of material properties. This review offers a comprehensive and up-to-date perspective on nanoprecipitation, focusing on its role in nanoparticle synthesis and its adaptability in designing diverse nanostructures. The review begins with the foundational principles of nanoprecipitation, emphasizing the impact of key parameters such as flow rate, mixing approach, injection rate, and Reynolds number on nanomaterial characteristics. It also discusses the influence of physicochemical factors, including solvent choice, polymer type, and drug properties. Various nanoprecipitation configurations-batch, flash, and microfluidic are examined for their specific advantages in controlling particle size, morphology, and internal structure. The review further explores the potential of nanoprecipitation to create complex nanostructures, such as core-shell particles, Janus nanoparticles, and porous and semiconducting polymer nanoparticles. Applications in biomedicine and other fields highlight nanoprecipitation's promise as a sustainable and tunable method for fabricating advanced nanomaterials. Finally, the review identifies future directions, including scaling microfluidic techniques, expanding compatibility with hydrophilic compounds, and integrating machine learning to further enhance the development of nanoprecipitation.},
}

@article {pmid40138794,
year = {2025},
author = {Zhang, L and Wang, K and Zhang, X and Liu, S and Jing, Z and Lu, J and Cui, X and Liu, Z},
title = {Research on the aerodynamic performance and bionic application of dragonfly wing corrugation.},
journal = {Bioinspiration & biomimetics},
volume = {},
number = {},
pages = {},
doi = {10.1088/1748-3190/adc5bc},
pmid = {40138794},
issn = {1748-3190},
abstract = {To investigate the aerodynamic performance of dragonfly wing corrugations under gliding conditions, a new method of corrugation deformation is proposed. Firstly, the coordinate transformation functions that describe the amplitude and camber deformation of the corrugation and numerical simulation model are established. Then the effects of the corrugation structural parameters on airfoil performance are investigated by orthogonal experiment. Subsequently, the optimal structural parameters are selected sequentially, and the mechanism of the corrugation producing a high lift-to-drag ratio is analyzed. The results show that the optimized corrugation parameters are: corrugation profile as profile 5, amplitude coefficient λ = 0.8, vertex x-coordinate a = 0.9c, vertex y-coordinate b = 0.04c. The optimal airfoil achieves the highest lift-to-drag ratio of 5.090, which is increased by 42.82% compared with the flat airfoil. The pressure surface corrugation can increase the pressure difference between the upper and lower surfaces, which is the main reason for the high lift-to-drag ratio. Finally, the bionic airfoils are built by arranging the corrugation on the FFA-W3-211 airfoil, which prove that the dragonfly corrugation with a low Reynolds number is also applicable to the wind turbine airfoil with a high Reynolds number, thereby increasing the lift-to-drag ratio of the prototype airfoil by 1.22%. .},
}

@article {pmid40121369,
year = {2025},
author = {Xia, T and Wei, N and Shi, L},
title = {Large eddy simulation on the wake characteristics of linearly stratified flow past a sphere.},
journal = {Scientific reports},
volume = {15},
number = {1},
pages = {9970},
doi = {10.1038/s41598-025-94870-w},
pmid = {40121369},
issn = {2045-2322},
support = {12172227//National Natural Science Foundation of China/ ; },
abstract = {In this study, Large Eddy Simulation (LES) has been employed to examine the influence of the Froude number (Fr) on the linearly stratified wake and internal waves behind a sphere at a subcritical Reynolds number of Re = 3700. Six distinct sets of models with varying Fr (Fr = 0.05, 0.25, 0.5, 1, 2, ∞) have been chosen to establish density linear stratification through the use of a User Defined Function (UDF). The analysis focuses on the impact of stratification on wake characteristics, velocity distribution, and the structure of internal waves within stratified flow. It is evident that density stratification plays a pivotal role in shaping wake structure. Notably, in stratified flows, wakes exhibit unique characteristics including the generation of internal waves, suppression of vertical velocity, and the emergence of oscillating wake patterns. The study reveals that a decrease in the Froude number leads to heightened vertical suppression of the wake and increased anisotropy of the velocity distribution. Furthermore, as the Froude number ascends from 0.05 to 2, the wake undergoes a transition from quasi-two-dimensional vortex shedding to three-dimensional turbulence.},
}

@article {pmid40117956,
year = {2025},
author = {Zhu, K and Huang, Y and Yang, L and Xuan, M and Zhou, T and He, Q},
title = {Motion control of chemically powered colloidal motors.},
journal = {Advances in colloid and interface science},
volume = {341},
number = {},
pages = {103475},
doi = {10.1016/j.cis.2025.103475},
pmid = {40117956},
issn = {1873-3727},
abstract = {Chemically powered colloidal motors can convert chemical energy into directional mechanical movement, making them promising for applications such as targeted drug delivery, environmental decontamination, and precision disease treatment. However, their self-propulsion is constantly disrupted by random Brownian motion, making precise control under low Reynolds number conditions highly challenging. This review provides a brief overview of the three main propulsion mechanisms of chemically powered colloidal motors. It also summarizes recent advances in motion control, including speed regulation and trajectory navigation. Finally, we discuss future directions for achieving more precise motion control. We hope this review will inspire further research on developing more effective and practical control strategies for colloidal motors.},
}

@article {pmid40117304,
year = {2025},
author = {Ogawa, T and Koyama, S and Omori, T and Kikuchi, K and de Maleprade, H and Goldstein, RE and Ishikawa, T},
title = {The architecture of sponge choanocyte chambers is well adapted to mechanical pumping functions.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {122},
number = {12},
pages = {e2421296122},
doi = {10.1073/pnas.2421296122},
pmid = {40117304},
issn = {1091-6490},
support = {JPMJSP2114//MEXT | Japan Science and Technology Agency (JST)/ ; JP24KJ0400//MEXT | Japan Society for the Promotion of Science (JSPS)/ ; JPMJPR2142//MEXT | JST | Precursory Research for Embryonic Science and Technology (PRESTO)/ ; 21H05303//MEXT | Japan Society for the Promotion of Science (JSPS)/ ; 21H05306//MEXT | Japan Society for the Promotion of Science (JSPS)/ ; 22H01394//MEXT | Japan Society for the Promotion of Science (JSPS)/ ; 21H04999//MEXT | Japan Society for the Promotion of Science (JSPS)/ ; 21H05308//MEXT | Japan Society for the Promotion of Science (JSPS)/ ; },
mesh = {Animals ; *Porifera/physiology ; *Flagella/physiology ; Models, Biological ; },
abstract = {Sponges, the basalmost members of the animal kingdom, exhibit a range of complex architectures in which microfluidic channels connect multitudes of spherical chambers lined with choanocytes, flagellated filter-feeding cells. Choanocyte chambers can possess scores or even hundreds of such cells, which drive complex flows entering through porous walls and exiting into the sponge channels. One of the mysteries of the choanocyte chamber is its spherical shape, as it seems inappropriate for inducing directional transport since many choanocyte flagella beat in opposition to such a flow. Here, we combine direct imaging of choanocyte chambers in living sponges with computational studies of many-flagella models to understand the connection between chamber architecture and directional flow. We find that those flagella that beat against the flow play a key role in raising the pressure inside the choanocyte chamber, with the result that the flow rate and mechanical pumping efficiency reach a maximum at a small outlet opening angle. Comparison between experimental observations and the results of numerical simulations reveal that the chamber diameter, flagellar wave number, and the outlet opening angle of the freshwater sponge Ephydatia muelleri, as well as several other species, are related in a manner that maximizes the mechanical pumping functions. These results indicate the subtle balances at play during morphogenesis of choanocyte chambers, and give insights into the physiology and body design of sponges.},
}

Animals
*Porifera/physiology
*Flagella/physiology
Models, Biological

@article {pmid40108425,
year = {2025},
author = {Fu, J and Du, M and Jing, J and Liu, H and Sun, J and Chen, W and Chen, Y},
title = {Prediction of pressure drop in heavy oil water ring based on modified two fluid model.},
journal = {Scientific reports},
volume = {15},
number = {1},
pages = {9557},
pmid = {40108425},
issn = {2045-2322},
support = {52106208//National Natural Science Foundation of China/ ; 2023NSFSC0924//Natural Science Foundation of Sichuan Province/ ; },
abstract = {Accurate prediction of pressure drop of the heavy oil-water ring flow in pipeline is of great significance for establishing an optimal drag reduction model and ensuring safe production. The effects of different factors on the flow pattern and pressure drop of heavy oil-water annular two-phase flow were systematically analyzed, and a standard two-fluid pressure drop prediction model for annular flow was established. By modifying the shear stress equation of oil-water interface and introducing the wave-flow theory to modify the shear stress equation of water wall, a pressure drop prediction model for the generalized concentric water ring was obtained to calculate the periodic fluctuations of oil phase. Furthermore, by introducing the comprehensive Reynolds number expression of eccentric water ring, the pressure drop prediction model for the generalized eccentric water ring was obtained to calculate the periodic fluctuations of oil phase. The results show that the pressure drop prediction accuracy of the concentric water ring for ultra-heavy oil is improved by 80% by using the modified pressure drop prediction model. The comprehensive Reynolds number expression of eccentric water ring can effectively reflect the influence of eccentric effect on shear stress of water wall and the calculation error is less than 20% by predicting the pressure drop of the generalized eccentric water ring with different density differences.},
}

@article {pmid40102431,
year = {2025},
author = {Gomaa, A and Mhrous, Y and Abdelmagied, MM},
title = {Investigation of the hydraulic and thermal characteristics of a double concentric tubes with an inner twisted spiral tube.},
journal = {Scientific reports},
volume = {15},
number = {1},
pages = {9301},
pmid = {40102431},
issn = {2045-2322},
abstract = {The characteristics of heat transfer and fluid flow of twisted spiral tubes with different pitches and depths have been investigated experimentally with respect to a conventional tube (smooth tube) as a particular reference. The effects of the twisted spiral pitch ratios, S/Dhy, depth ratios, H/Dhy, Reynolds number and flow arrangement on the thermal performance of a twisted spiral tube heat exchanger are investigated. Three twisted spiral tubes with different pitches, S, of 3.9, 5.2 and 8.2 mm corresponding to twisted spiral pitch ratios, S/Dhy, of 0.278, 0.372 and 0.586; besides three twisted spiral tubes at different depths, H, of 0.6, 0.95, and 1.15 mm corresponding to twisted spiral height ratio, H/Dhy, of 0.043, 0.068 and 0.082 are experimentally examined in this study. The Reynolds number, Re, ranges in both inner tube side and annular side are 5000-50,000 and 1400-10,400, respectively. The results revealed that the twisted spiral pitch ratios S/Dhy of the 0.278achieved an enhancement of Nu by 38% compare to the smooth tube with a corresponding increase of 33.2% in the f. Also, the twisted spiral depths ratios, H/Dhy, of 0.082 achieved higher Nu by 44.9%, compared to the smooth tube with a corresponding increase of 36.4% in the f. The thermal performance criteria reached 1.93 and 2.03 at S/Dhy of 0.278 and H/Dhy of 0.082, respectively. New correlations to expect Nuc and fc were predicted.},
}

@article {pmid40085914,
year = {2025},
author = {Kiran, KV and Kumar, K and Gupta, A and Pandit, R and Ray, SS},
title = {Onset of Intermittency and Multiscaling in Active Turbulence.},
journal = {Physical review letters},
volume = {134},
number = {8},
pages = {088302},
doi = {10.1103/PhysRevLett.134.088302},
pmid = {40085914},
issn = {1079-7114},
abstract = {Recent results suggest that highly active, chaotic, nonequilibrium states of living fluids might share much in common with high Reynolds number, inertial turbulence. We now show, by using a hydrodynamical model, the onset of intermittency and the consequent multiscaling of Eulerian and Lagrangian structure functions as a function of the bacterial activity. Our results bridge the worlds of low and high Reynolds number flows as well as open up intriguing possibilities of what makes flows intermittent.},
}

@article {pmid40077274,
year = {2025},
author = {Weng, C and Wang, Z and Luo, X and Li, H},
title = {Numerical Analysis of Steady-State Multi-Field Coupling in Electro-Fused Magnesia Furnace.},
journal = {Materials (Basel, Switzerland)},
volume = {18},
number = {5},
pages = {},
doi = {10.3390/ma18051049},
pmid = {40077274},
issn = {1996-1944},
support = {No. 2023-GX-102//Special Project for Transformation of Scientific and Technological Achievements of Qinghai Province/ ; 2018YFC1903805//the National Key Research and Development Program of China/ ; 2022YFC2904305//the National Key Research and Development Program of China/ ; 51604059//National Natural Science Foundation of China/ ; },
abstract = {The internal conditions of the high-temperature molten pool in an electro-fused magnesia furnace (EFMF) are difficult to measure, and the temperature distribution-energy conservation relationship in the EFMF cannot be effectively evaluated. Assuming that the feeding speed is constant, the heat absorbed by the newly added raw materials is equal to the rated power minus the heating power required to maintain thermal balance. Therefore, the EFMF can be approximately described by a steady-state model. In order to analyze the state of the molten pool of EFMF at different smelting stages, this study first constructed a three-dimensional steady-state multi-physics field numerical simulation model. The calculations show that the equivalent resistance of the molten pool varies approximately between 1 mΩ and 0.4 mΩ. Furthermore, the equivalent reactance produced by the whole conductive circuit is almost of the same order as the resistance. The Reynolds number of the convection inside the molten pool exceeds 105, which means that the flow inside the molten pool is forced convection dominated by the Lorentz force. Moreover, the turbulence makes the temperature uniformity of the molten pool (the temperature gradient near the solid-liquid interface is approximately within 300 K/m) far greater than that of the unmelted raw materials with very low thermal conductivity (the average temperature gradient reaches over 1000 K/m); the respective proportions of arc power and Joule heating power can be predicted by the model. When the molten pool size is small, the proportion of Joule heating power is high, reaching about 20% of the rated power (3700 kVA); as the molten pool size increases, the convection effect is relatively weakened, and the proportion of Joule heating power also decreases accordingly, only 5% to 10%; the model prediction and experimental estimation results are in good agreement, which makes it feasible to conduct a quantitative analysis of the power distribution in different smelting stages.},
}

@article {pmid40051847,
year = {2025},
author = {Fardin, MM and Hossain, MS and Hasan, MN},
title = {CFD based neural network model framework for mixed convection in a lid-driven cavity with conductive cylinder.},
journal = {Heliyon},
volume = {11},
number = {4},
pages = {e42637},
pmid = {40051847},
issn = {2405-8440},
abstract = {The current study investigates the application of an Artificial Neural Network (ANN) model to analyze and predict mixed convection heat transfer within a 2-dimensional square cavity with a conductive cylinder at the centre. The top lid of the cavity is maintained at a constant cold temperature and slides with a constant linear velocity, while the bottom wall is heated to maintain a constant temperature. The governing equations are discretized using Galerkin Weighted Residual Method and numerically solved using Gauss Quadrature procedure. The ANN model is trained using the data derived from CFD simulations and used to predict the heat transfer performance quantitatively and qualitatively. The setup is investigated for a wide range of Richardson numbers (0.1≤ Ri ≤ 10.0), Reynolds numbers (50 ≤ Re ≤ 250) and cylinder diameters (0.1≤ D/L ≤ 0.8). Heat transfer performance is evaluated from the average Nusselt number along the heated bottom wall. Correlations are established showing dependency of Nusselt number on Ri, Re and D/L. Velocity and thermal fields are expressed by streamlines and isothermal contours. The study shows that higher Richardson and Reynolds numbers lead to an enhancement in the overall heat transfer. But for larger cylinder diameters, heat transfer is mostly dependent on Reynolds number. It is also revealed that substantial improvements in computational efficiency are achieved by the ANN model as it has reduced 82 % of computation time and 83 % of storage requirements to predict the results by maintaining mean absolute error below 0.1 %. The study provides an insight that ANN modelling could open a new dimension to the heat transfer research field and significantly reduce the requirement of time and resources to solve complex problems.},
}

@article {pmid40046270,
year = {2025},
author = {Muhamad Pauzi, A and Iacovides, H and Cioncolini, A and Li, H and Nabawy, MRA},
title = {Application of URANS Simulation and Experimental Validation of Axial Flow-Induced Vibrations on a Blunt-End Cantilever Rod for Nuclear Applications.},
journal = {Arabian journal for science and engineering},
volume = {50},
number = {5},
pages = {3435-3455},
pmid = {40046270},
issn = {2193-567X},
abstract = {Fretting wear caused by flow-induced vibration (FIV) is a leading cause of fuel failure in light water nuclear reactors. This study describes a numerical methodology, validated with dedicated experiments, for predicting flow-induced vibrations in cantilever rods exposed to axial water flow, a paradigmatic configuration informative for fuel rods in water-cooled nuclear reactor cores. Utilising strong two-way fluid-structure interaction (FSI) simulations with an efficient computational approach, the study focuses on two key aspects of self-excited FIV: the dominant vibration frequency and the amplitude of the vibration. Correctly reproducing the former depends on optimising the solid domain and FSI coupling, while the latter hinges on the fluid solver's ability to accurately replicate unsteady flow behaviour, especially in areas of flow separation. Two unsteady Reynolds averaged Navier-Stokes turbulence models, both being high-Reynolds number versions, and several discretisation schemes for the convection transport are evaluated for their capacity to reproduce the correct unsteady flow behaviour. When the axial flow is directed from the free end to the fixed end of the rod, both the Eddy viscosity model k- ω SST and the Reynolds stress model by Launder, Reece, and Rodi reliably predicted the frequency and amplitude of vibrations for a Reynolds number range between 16.4k and 61.7k. When the flow direction is reversed, while vibration frequencies were accurately modelled, replicating precise unsteady flow behaviour proved more challenging. The study underscores the importance of properly resolving the flow in areas of flow separation to achieve accurate simulation of unsteady flow behaviour.},
}

@article {pmid40034269,
year = {2025},
author = {Jahin, AS and Samin, JH and Chhoa, MF and Faisal, F and Nokib, MHI and Rabby, MII},
title = {Computational study of thermofluidic characteristics of Al2O3-Cu hybrid nanofluids in backward facing step channel with varying step angles.},
journal = {Heliyon},
volume = {11},
number = {4},
pages = {e42638},
pmid = {40034269},
issn = {2405-8440},
abstract = {Backward-Facing Step (BFS) channels are frequently utilized in technical implementation due to their ability to model intricate fluid flow patterns, such as recirculation zones, which have significant impacts on thermal exchange rates. This research investigates the thermal and heating efficiency of Al2O3-Cu hybrid nanofluids in a BFS channel, focusing on the effects of varying step angles and Reynolds numbers (Re) on thermal efficiency. ANSYS Fluent (2021 R2) was used to analyze Al2O3-Cu nanofluids across Reynolds numbers (500-800), step angles (70°, 75°, 80°, and 85°), and particle volumes (1%-4%) applying the finite volume method. The results demonstrate that as the Reynolds number increases, the Nusselt number rises by an average of 18.505 %. In contrast, varying the step angle results in an average increase of 4.94 %. It is also observed that an increase in volume fraction of nanoparticles enhances the Nusselt number due to the superior thermal conductivity of the Al2O3-Cu nanofluid. Additionally, a positive correlation between step angle, skin friction coefficient, and pressure drop was observed.},
}

@article {pmid40019202,
year = {2025},
author = {Lopez, M and Benchikh Le Hocine, AE and Kone, TC and Dupont, T and Panneton, R},
title = {Inertial effects on single-perforation plates resistivity at high flow rates: Computational fluid dynamics and experimental studies.},
journal = {The Journal of the Acoustical Society of America},
volume = {157},
number = {2},
pages = {1512-1522},
doi = {10.1121/10.0035642},
pmid = {40019202},
issn = {1520-8524},
abstract = {This article is focused on the viscous and inertial effects on airflow resistivity of periodic arrays of single-perforation plates spaced by thin air cavities. Analyzing this effect would provide better insight into losses within the material, including additional losses due to increasing sound excitation levels. In this way, the material pressure drop is predicted by computational fluid dynamics function (CFD) of the flow rate for corresponding pore Reynolds numbers between 0.3 and 1500. The static airflow resistivity coefficient is determined by the linear part of the pressure drop (viscous effect) and the Forchheimer coefficient from the nonlinear part of the pressure drop (inertial effect). Both coefficients are determined on the entirety of the material (globally) and at the plate levels (locally). Good agreement is observed between CFD predictions and experimental measurements on the whole range of studied Reynolds numbers. By locally investigating the pressure drops, the observations show that the viscous effects are constant through the material. With increasing pore Reynolds number, inertial effects of the first plate dominate over those of the other plates. The consideration of the local inertial effect will be a key component in the acoustic modeling of this type of material under high sound excitation levels.},
}

@article {pmid40011611,
year = {2025},
author = {Gomaa, A and Gamal, Y and Abdelmagied, MM},
title = {Enhancement of thermofluid characteristics via a triple-helical tube heat exchanger.},
journal = {Scientific reports},
volume = {15},
number = {1},
pages = {6978},
pmid = {40011611},
issn = {2045-2322},
abstract = {An investigation of the thermal and hydraulic performance of a novel triple-helical tube heat exchanger, the THTHE, is presented. The novel design is a modified design of a DHTHE created by adding a third tube to a DHTHE tube. The third passage is expected to enhance the thermal performance of the DHTHE as a result of an increase in the temperature gradient between the hot and cold fluids. The effects of the coil radius, inner annulus spacing, water inlet temperature, direction of flow arrangement, and Dean number were explored. Five test samples with different coil radii of 150 mm, 125 mm, and 90 mm and different inner annulus spacings of 6.2 mm, 9 mm, and 12 mm were examined. The test samples were designed, fabricated, and tested to demonstrate the influence of design parameters on the thermal and hydraulic performance of the triple-helical tube heat exchanger. The experimental runs were conducted on the hot water side with the water inlet temperature Th,i ranging from 50:80 °C. Moreover, at Dean number 400 ≤ Deh ≤ 5500, corresponding to Reynolds number 2700 ≤ Reh ≤ 31,000. Compared with the double-helical tube heat exchanger, the THTHE resulted in a higher Nusselt number by 146.1% and 109.3% for both the counterflow and parallel-flow arrangements, respectively. Furthermore, lowering the hot water source temperature from 80 to 50 °C results in a 60.6% increase in the Nusselt number of 60.6%, with no increase in the pumping power. Additionally, with a decreasing coil radius from 150 to 90 mm and inner annulus spacing from 12 to 6.2 mm, a significant increase in Nu occurs by 58.2% and 130.4%, respectively. A general correlation was presented for predicting Nu, f, and ε.},
}

@article {pmid40009542,
year = {2025},
author = {Zhang, Y and Wang, X and Han, J and Xiao, J and Yong, Y and Yu, C and Yue, N and Sun, J and He, K and Hao, W and Zhang, T and Wang, B and Wang, D and Yang, X},
title = {Dynamic simulations of feeding and respiration of the early Cambrian periderm-bearing cnidarian polyps.},
journal = {eLife},
volume = {12},
number = {},
pages = {},
doi = {10.7554/eLife.90211},
pmid = {40009542},
issn = {2050-084X},
support = {42372012//Natural Science Foundation of China/ ; XDB26000000//Chinese Academy of Sciences/ ; D17013//Ministry of Education of China/ ; BJ11060//Northwest University/ ; 2023YFF0803601//National Key Research and Development Program of China/ ; Z6122059//Linyi University/ ; 41720104002//Natural Science Foundation of China/ ; 41911530236//Natural Science Foundation of China/ ; },
mesh = {Animals ; *Feeding Behavior/physiology ; *Fossils ; *Respiration ; *Cnidaria/physiology/anatomy & histology ; China ; Computer Simulation ; Hydrodynamics ; },
abstract = {Although fossil evidence suggests the existence of an early muscular system in the ancient cnidarian jellyfish from the early Cambrian Kuanchuanpu biota (ca. 535 Ma), south China, the mechanisms underlying the feeding and respiration of the early jellyfish are conjectural. Recently, the polyp inside the periderm of olivooids was demonstrated to be a calyx-like structure, most likely bearing short tentacles and bundles of coronal muscles at the edge of the calyx, thus presumably contributing to feeding and respiration. Here, we simulate the contraction and expansion of the microscopic periderm-bearing olivooid Quadrapyrgites via the fluid-structure interaction computational fluid dynamics (CFD) method to investigate their feeding and respiratory activities. The simulations show that the rate of water inhalation by the polyp subumbrella is positively correlated with the rate of contraction and expansion of the coronal muscles, consistent with the previous feeding and respiration hypothesis. The dynamic simulations also show that the frequent inhalation/exhalation of water through the periderm polyp expansion/contraction conducted by the muscular system of Quadrapyrgites most likely represents the ancestral feeding and respiration patterns of Cambrian sedentary medusozoans that predated the rhythmic jet-propelled swimming of the modern jellyfish. Most importantly for these Cambrian microscopic sedentary medusozoans, the increase of body size and stronger capacity of muscle contraction may have been indispensable in the stepwise evolution of active feeding and subsequent swimming in a higher flow (or higher Reynolds number) environment.},
}

Animals
*Feeding Behavior/physiology
*Fossils
*Respiration
*Cnidaria/physiology/anatomy & histology
China
Computer Simulation
Hydrodynamics

@article {pmid40007569,
year = {2025},
author = {Mohan, A and Ramanan, SR},
title = {Surface imprinted microhelical magnetic polymer nanocomposite fibers for targeted lysozyme separation.},
journal = {Nanoscale advances},
volume = {},
number = {},
pages = {},
pmid = {40007569},
issn = {2516-0230},
abstract = {Magnetic microhelical structures have recently drawn attention as microswimmers capable of mimicking bacterial propulsion in the low Reynolds number regime. Such structures can be used in microfluidic bioseparation or targeted delivery and their interaction with proteins is extremely important. In this study we fabricated silica coated magnetic microhelices resembling artificial bacterial flagella like structures via electrospinning magnetite nanoparticle incorporated polystyrene nanocomposite solution followed by silica sol coating. Two model proteins, Lysozyme (Lyz) and Bovine Serum Albumin (BSA), were used for protein imprinting along with a polydopamine layer on the magnetic microhelical substrates. The adsorption mechanism of lysozyme on the molecularly imprinted support system was analyzed using adsorption model fitting (Langmuir, Freundlich and Temkin). Adsorption capacity, selective binding and imprinting factor values were calculated for both imprinted (Lyz and BSA) and non-imprinted samples. A significantly higher adsorption capacity was obtained compared to previously reported studies.},
}

@article {pmid40001473,
year = {2025},
author = {Zhuang, XY and Lo, CJ},
title = {Decoding Bacterial Motility: From Swimming States to Patterns and Chemotactic Strategies.},
journal = {Biomolecules},
volume = {15},
number = {2},
pages = {},
doi = {10.3390/biom15020170},
pmid = {40001473},
issn = {2218-273X},
support = {NSTC-109-2628-M-008-01-MY4//NSTC/ ; NSTC 113-2112-M-001-059-MY3.//NSTC/ ; },
mesh = {*Chemotaxis ; *Flagella/physiology ; *Bacteria/metabolism ; Bacterial Physiological Phenomena ; Movement ; },
abstract = {The bacterial flagellum serves as a crucial propulsion apparatus for motility and chemotaxis. Bacteria employ complex swimming patterns to perform essential biological tasks. These patterns involve transitions between distinct swimming states, driven by flagellar motor rotation, filament polymorphism, and variations in flagellar arrangement and configuration. Over the past two decades, advancements in fluorescence staining technology applied to bacterial flagella have led to the discovery of diverse bacterial movement states and intricate swimming patterns. This review provides a comprehensive overview of nano-filament observation methodologies, swimming states, swimming patterns, and the physical mechanisms underlying chemotaxis. These novel insights and ongoing research have the potential to inspire the design of innovative active devices tailored for operation in low-Reynolds-number environments.},
}

*Chemotaxis
*Flagella/physiology
*Bacteria/metabolism
Bacterial Physiological Phenomena
Movement

@article {pmid39972743,
year = {2025},
author = {Verma, S and Seshasayanan, K},
title = {Effects of radial conductivity variation on the Ponomarenko dynamo.},
journal = {Physical review. E},
volume = {111},
number = {1-2},
pages = {015207},
doi = {10.1103/PhysRevE.111.015207},
pmid = {39972743},
issn = {2470-0053},
abstract = {We study the effects of conductivity variation on the Ponomarenko dynamo. Taking monotonically increasing, decreasing and sinusoidally varying radial profiles, we study the kinematic dynamo problem. The threshold of the dynamo, given by the critical magnetic Reynolds number Rm_{c},
is found to strongly depend on the form of conductivity variation near the discontinuity of the velocity field where the shear is dominant. For monotonically varying profiles in the limit of sharp variation, this threshold maps to the problem of the dynamo with a jump in conductivity, while for the sinusoidal profile with large variations or wave numbers, the threshold increases due to effective diffusivity arising from the rapid changes in conductivity. Far from the threshold, it is found that the growth rate depends only on the local gradient of the conductivity near the discontinuity, with the opposite sign of shear and conductivity gradient leading to a larger growth rate, thereby aiding the dynamo instability in regenerating B_{ϕ}
from B_{r}.
We calculate the expression for the growth rate in the limit of large Rm(≫1) and find that the conductivity variation leads to a modification proportional to the local gradient of conductivity times Rm^{-1/2}.
This correction is found to depend only on the local gradient of the conductivity at the discontinuity. Similar dependencies are found for realistic, smooth velocity profiles and for different magnetic boundary conditions.},
}

@article {pmid39958364,
year = {2025},
author = {Bose, C and Bruce, C and Viola, IM},
title = {Porous plates at incidence.},
journal = {Theoretical and computational fluid dynamics},
volume = {39},
number = {2},
pages = {19},
pmid = {39958364},
issn = {0935-4964},
abstract = {This paper investigates the effect of permeability on two-dimensional rectangular plates at incidences. The flow topology is investigated for Reynolds number (Re) values between 30 and 90, and the forces on the plate are discussed for R e = 30 , where the wake is found to be steady for any value of the Darcy number (Da) and the flow incidence (α). At R e = 30 , for a plate normal to the stream and vanishing Da, the wake shows a vortex dipole with a stagnation point on the plate surface. With increasing Da, the separation between the vortex dipole and the plate increases; the vortex dipole shortens and is eventually annihilated at a critical Da. For any value of Da below the critical one, the vortex dipole disappears with decreasing α . However, at low Da, the two saddle-node pairs merge at the same α , annihilating the dipole; while at high Da, they merge at different α , resulting in a single recirculating region for intermediate incidences. The magnitudes of lift, drag, and torque decrease with Da. Nevertheless, there exists a range of Da and α , where the magnitude of the plate-wise force component increases with Da, driven by the shear on the plate's pressure side. Finally, the analysis of the fluid impulse suggests that the lift and drag reduction with Da are associated with the weakening of the leading and trailing edge shear layer, respectively. The present findings will be directly beneficial in understanding the role of permeability on small permeable bodies.},
}

@article {pmid39953100,
year = {2025},
author = {Zhang, T and Li, F and Fan, J},
title = {Impact of corner optimization measures on the interference effects between two square section buildings.},
journal = {Scientific reports},
volume = {15},
number = {1},
pages = {5558},
pmid = {39953100},
issn = {2045-2322},
support = {//National Natural Science Foundation of China/ ; },
abstract = {Wind-induced interference effects occur between high-rise twin buildings. To elucidate the impact of aerodynamic optimization measures on the interference effects between high-rise buildings, large eddy simulations (LES) were conducted to analyze the wind load characteristics of buildings with varying spacing. The simulation results were compared with experimental data and previous studies to validate the method's accuracy. To investigate the influence of various aerodynamic corner optimizations on interference effects between high-rise buildings, LES was employed to simulate wind load characteristics. Simulation results were compared with experimental data and previous studies to ensure the method's accuracy. Three corner treatments-chamfered, rounded, and recessed-were applied to the model, with a corner modification rate of 10%. Under wind field conditions corresponding to a Reynolds number (Re) of 22,000, 10 simulated schemes with spacing ratios (B/L) ranging from 1.2 to 8 were considered, where B represents the center-to-center distance between two square cylinders, and L denotes the side length of each square cylinder. The aerodynamic coefficients, flow field mechanisms, and vorticity of the two side-by-side square cylinders under three corner treatments were compared. Additionally, peak factors were calculated based on predefined measurement points to further assess differences in interference factors. Using the Lorentz function, the peak fitting curve of the wind pressure probability density was compared with the Gaussian fitting curve. The analysis indicates that the wind pressure shielding effect is most pronounced for the rounded corner square cylinder, while the amplification effect is strongest for the chamfered corner square cylinder. At critical spacing, the adjacent facades of the recessed corner square cylinders exhibited a bimodal distribution in wind pressure probability density.},
}

@article {pmid39946945,
year = {2025},
author = {Lu, Y and Chu, K and Hua, Z and Gao, C and Liu, Y},
title = {The response of PFAA mobility in highly contaminated sediment to sluice operation: Coupled effects of scour behavior and physicochemical properties.},
journal = {Water research},
volume = {276},
number = {},
pages = {123260},
doi = {10.1016/j.watres.2025.123260},
pmid = {39946945},
issn = {1879-2448},
abstract = {Despite their widespread occurrence and significant environmental implications, the influence of sluice operations on the mobility of perfluoroalkyl acid (PFAA) in riverine sediments remains largely unexplored. To address this gap, a series of flume experiments were conducted to simulate the sedimentary migration of PFAA under the turbulent conditions generated by opening a sluice. Our study provides novel insights into the mechanisms by which plunging turbulence modulates the transfer of sedimentary PFAAs across the sediment‒water interface. Significant transient release effects were observed in the dissolved and suspended particulate matter (SPM) phases of PFAA, with total concentrations maintaining relative stability over extended periods following disturbance. The fluviraption of plunging turbulence increased PFAA concentrations in the surface sedimentary and porewater phases but weakened the adsorption performance of resuspended particles for the chemicals in the lower reach of the sluice. The instantaneous release of PFAA from sediment, fueled by turbulence, was identified as the primary driver of total mass transfer across the interface, increasing exponentially with the Reynolds number (Rex, R[2]=0.99, p < 0.01). Notably, the peak PFAA release flux in the SPM phase lagged behind that in the dissolved phase, underscoring the dynamic interplay between phases. A structural equation model (SEM) revealed that plunging turbulence indirectly governs the cross-interface transfer of sedimentary PFAA by altering environmental physicochemical parameters and enhancing porewater diffusion. This finding underscores the complex, coupled effects of scour behavior and physicochemical properties on PFAA fate. Our study offers a unique perspective on the dynamic mechanisms underlying PFAA multimedia migration under sluice operation, contributing valuable insights for managing and regulating these emerging contaminants in aquatic environments.},
}

@article {pmid39944342,
year = {2025},
author = {Biswas, S and Harish, R},
title = {Effect of unsteady cavitation on hydrodynamic performance of NACA 4412 Hydrofoil with novel triangular slot.},
journal = {Heliyon},
volume = {11},
number = {3},
pages = {e42266},
pmid = {39944342},
issn = {2405-8440},
abstract = {This study demonstrates the hydrodynamic performance of a modified NACA 4412 hydrofoil and compares it with the base NACA 4412 hydrofoil in the presence of cavitation. A triangular slot has been introduced at the mid-section of the suction side of the hydrofoil to modify the flow characteristics and assess its effects on the performance at different operational cavitation numbers spanning from 0.8 to 2.5, and at different angles of attack ranging from 4° to 16°. The performance metrics considered include the coefficient of lift, coefficient of drag, and the lift-to-drag ratio. The Reynolds number considered in this study is approximately 1.5 million. The SST k-ω turbulence model, homogeneous mixture multiphase model, and Schnerr& Sauer cavitation model have been employed in this study. At lower cavitation numbers, the modified hydrofoil is better able to control cavitation phenomena compared to the base hydrofoil. However, at higher cavitation numbers, the base hydrofoil exhibits slightly better performance than the modified hydrofoil in terms of lift-to-drag ratio, despite having a lower lift coefficient. Furthermore, the modified hydrofoil demonstrates improved performance at 4°, 8°, and 16° angles of attack, while the base hydrofoil performs better at a 12° angle of attack. It was also observed that stalling occurs at a 16° angle of attack for the base hydrofoil, whereas the modified hydrofoil successfully avoids stalling.},
}

@article {pmid39941600,
year = {2025},
author = {Nuche, J and Ponz, I and Sánchez Sánchez, V and Bóbeda, J and Gaitán, Á and López-Linares, K and García-Cosío, MD and Sarnago Cebada, F and González, JS and Arribas Ynsaurriaga, F and Ruíz-Cabello, J and Ibáñez, B and Delgado, JF},
title = {Four-Dimensional Magnetic Resonance Pulmonary Flow Imaging for Assessing Pulmonary Vasculopathy in Patients with Postcapillary Pulmonary Hypertension.},
journal = {Journal of clinical medicine},
volume = {14},
number = {3},
pages = {},
doi = {10.3390/jcm14030929},
pmid = {39941600},
issn = {2077-0383},
support = {PI17/01569//Instituto de Salud Carlos III/ ; },
abstract = {Background: Noninvasive techniques for diagnosing combined postcapillary pulmonary hypertension (CpcPH) are unavailable. Objective: To assess the diagnostic performance of cardiac magnetic resonance (CMR)-based four-dimensional (4D)-flow analysis in identifying CpcPH. Methods: Prospective observational study of heart failure (HF) patients with suspected pulmonary hypertension (PH) who underwent simultaneous CMR and right heart catheterization. The 4D-flow biomarkers were calculated using an automatic pipeline. A predictive model including 4D-flow biomarkers associated with CpcPH with a p-value < 0.20 was built to determine the diagnostic performance of 4D-flow analysis to identify CpcPH. Results: A total of 46 HF patients (55.4 ± 14 years, 63% male) with confirmed PH (19 [41%] isolated postcapillary PH [IpcPH], 27 [59%] CpcPH) were included. No differences were found in baseline characteristics, echocardiography, or CMR anatomical and functional parameters, except for a higher Doppler-estimated systolic pulmonary pressure and larger pulmonary artery in CpcPH patients. The 4D-flow CMR analysis was performed in 31 patients (67%). The maximal peak velocity (67.1 [62.2-77.5] cm/s-IpcPH vs. 58.2 [45.8-66.0] cm/s-CpcPH; p = 0.021) and maximal helicity (339.9 [290.0-391.8]) cm/s[2]-IpcPH vs. 226.0 (173.5-343.7) cm/s[2]-CpcPH; p = 0.026) were significantly lower in patients with CpcPH. A maximal multivariable model including sex, maximal average, and peak velocities, Reynolds number, flow rate, and helicity showed fair diagnostic performance (area under the curve: 0.768 [95%-CI: 0.572-0.963]; sensitivity: 100%; specificity: 55%). Conclusions: In HF patients with PH, 4D-flow-derived maximal peak velocity and maximal helicity were significantly lower in CpcPH patients. A multiparametric model including maximal 4D-flow-derived biomarkers showed good diagnostic performance for identifying CpcPH.},
}

@article {pmid39938336,
year = {2025},
author = {Rüttgers, M and Waldmann, M and Ito, S and Wüstenhagen, C and Grundmann, S and Brede, M and Lintermann, A},
title = {Patient-specific lattice-Boltzmann simulations with inflow conditions from magnetic resonance velocimetry measurements for analyzing cerebral aneurysms.},
journal = {Computers in biology and medicine},
volume = {187},
number = {},
pages = {109794},
doi = {10.1016/j.compbiomed.2025.109794},
pmid = {39938336},
issn = {1879-0534},
abstract = {Magnetic resonance velocimetry (MRV) measurements were used as inflow conditions for lattice-Boltzmann (LB) simulations to analyze cerebral aneurysms. Unlike previous studies on larger vascular structures, aneurysm analysis involves smaller scales and higher pressure differences, making near-wall velocity measurements challenging with standard 3 Tesla scanners. To address this, the aneurysm geometry was scaled 5-fold for sufficient magnetic resonance velocimetry (MRV) resolution, with inflow measurements interpolated onto the simulation grid while ensuring dimensionless equivalence via the Reynolds number. Zero-velocity points were included near walls to enforce the no-slip condition if measurement points exceed the simulation domain. The proposed interpolation-based inflow method was compared to a nearest-neighbor approach and a parabolic velocity profile. It achieved the best agreement with MRV centerline velocity measurements (mean error: 3.12%), followed by the nearest-neighbor method (3.18%) and the parabolic profile (9.85%). The parabolic inflow led to centerline velocity overpredictions and total pressure underpredictions, while the nearest-neighbor approach underestimated the wall shear stress (WSS) and exhibited inconsistencies in wall normal stress (e.g., maximum WSS was 18.3% lower than with interpolation). Using the interpolated inflow method, Newtonian and non-Newtonian flows based on the Carreau-Yasuda model were compared. The non-Newtonian model showed lower centerline velocities and total pressure but higher WSS than the Newtonian case. These findings highlight the importance of accurate, patient-specific inflow conditions and the necessity of non-Newtonian modeling for reliable WSS predictions. Combining MRV measurements with non-Newtonian LB simulations provides a robust framework for personalized cerebral aneurysm hemodynamic evaluation.},
}

@article {pmid39937070,
year = {2025},
author = {Beckedorff, L and Caridi, GCA and Soldati, A},
title = {Jet-stirred homogeneous isotropic turbulent water tank for bubble and droplet fragmentation.},
journal = {The Review of scientific instruments},
volume = {96},
number = {2},
pages = {},
doi = {10.1063/5.0218326},
pmid = {39937070},
issn = {1089-7623},
abstract = {We present a new jet-stirred turbulent water tank designed to produce homogeneous isotropic turbulence, focusing on multiphase flow phenomena. In particular, the facility features a high Taylor-microscale Reynolds number of O(103) that can ensure a large inertial range and is suitable for studying the breakage of droplets and bubbles in line with the Kolmogorov-Hinze theory. The turbulence is created in an octagonal horizontal water tank by two opposing jet arrays, where each jet can release continuous flow with adjustable velocity. The acrylic section design allows optical access for six high-speed cameras to apply time-resolved visualization techniques. Using 3D Lagrangian particle tracking, we provide a complete statistical characterization of the turbulence field: our measurements reveal a maximum turbulence anisotropy of 10% in the center of the water tank with an energy dissipation rate up to ɛ = 0.3 m2 s-3. This high energy dissipation rate is sufficient to trigger the breakage of bubbles and droplets of O(1-10 mm), which falls in the turbulence inertial range. Furthermore, we demonstrate the capability of our imaging system and reconstruction methods for multiphase flow studies with examples of full 3D topology reconstruction coupled with surrounding flow measurements.},
}

@article {pmid39924563,
year = {2025},
author = {Rezapour, M and Esmaiili, M and Mahmoudian, M and Sarand, AB},
title = {Design and modeling of a nanocomposite system for demineralization of sweet whey.},
journal = {Scientific reports},
volume = {15},
number = {1},
pages = {4824},
pmid = {39924563},
issn = {2045-2322},
mesh = {*Nanocomposites/chemistry ; *Whey/chemistry/metabolism ; *Whey Proteins/chemistry/metabolism ; *Graphite/chemistry ; Hydrogen-Ion Concentration ; Neural Networks, Computer ; Filtration/methods ; Membranes, Artificial ; Temperature ; },
abstract = {This research investigates the design of a nanofiltration (NF) system based on a nanocomposite membrane containing graphene oxide (GO) for the demineralization of sweet whey and the modeling the NF process. The effects of various process variables, including, transmembrane pressure (TMP), Reynolds number, feed pH, and temperature, on the rejection of the minerals were surveyed. Consequently, the recovery of whey proteins from industrial whey using fabricated membranes in a cross-flow membrane module was also investigated. Among the input variables, the pH of the whey solution has the greatest effect on membrane flux and salt rejection performance. In the dead-end filtration system, the highest flux was achieved for the GO-modified membrane under laboratory conditions with a pressure of 10 bar and a pH of 6. The dynamic flux behavior of whey output and salt rejection from whey was modeled using convolutional neural network (CNN) machine learning tools. Linear and non-linear correlations demonstrated that the CNN model correlates well with experimental data on dynamic flux (R[2]-1.00). Overall, this study on dynamic flux and rejection of minerals from whey using CNN modeling can improve optimal conditions for whey demineralization and reduce laboratory testing costs by predicting the results of untested experimental variables.},
}

*Nanocomposites/chemistry
*Whey/chemistry/metabolism
*Whey Proteins/chemistry/metabolism
*Graphite/chemistry
Hydrogen-Ion Concentration
Neural Networks, Computer
Filtration/methods
Membranes, Artificial
Temperature

@article {pmid39905159,
year = {2025},
author = {Aziz, MA and Khalifa, MA and Abdelrahman, MA and Elshimy, H and Elsayed, AM},
title = {Multi-slotted airfoil design for enhanced aerodynamic performance and economic efficiency.},
journal = {Scientific reports},
volume = {15},
number = {1},
pages = {4290},
pmid = {39905159},
issn = {2045-2322},
abstract = {Recently, slotted airfoils have been introduced as a passive flow control approach. The slotted airfoil method resulted in stall delay and enhanced the lift coefficient. The single-slot airfoil is unable to delay stall if the flow is injected downstream of the separation point at the stall angle of attack. A multi-slot airfoil ensures air is injected along the airfoil suction side, delaying stalls over a large range of AOA. The current study focuses on enhancing wind turbine blades' efficiency by utilizing a novel multi-slot NACA23012C airfoil design as a passive control approach. A numerical study of the optimal grid number was carried out, followed by validating the numerical model with previous experimental results in the literature. The numerical study is followed by a study of the effect of the number of airfoil slots: one, two, three, four, five, and six. The characteristics of the flow field were analyzed to explain the benefit of applying multi-slotted on the aerodynamic performance of an airfoil with a high AOA at Reynolds number 2.74 × 10[5]. The findings showed a significant improvement in the lift coefficient values and the delayed stall AOA for multi-slot airfoils compared to the clean and single-slot airfoils. Increasing the slots number is effective up to four slots. The four-slot airfoil improved lift by 15.8%, and the two slots achieved a 22.31% CL/CD increase. Future work could optimize slot geometry, validate findings experimentally, and study dynamic and 3D effects.},
}

@article {pmid39879652,
year = {2025},
author = {Winter, A and Schoombie, J and Smith, L},
title = {A numerical approach to model and analyse geometric characteristics of a grey-headed albatross aerofoil in flight.},
journal = {Bioinspiration & biomimetics},
volume = {},
number = {},
pages = {},
doi = {10.1088/1748-3190/adaff4},
pmid = {39879652},
issn = {1748-3190},
abstract = {Limited research exists on the 3D geometric models and aerodynamic characteristics of the Grey-headed Albatross (GHA). Despite existing methods for extracting bird wing cross-sections, few studies consider deflections due to aerodynamic pressure. With the GHA known for its exceptional flight speed and purported wing-lock mechanism, it offers a valuable subject for studying fixed-wing aerodynamicsin nature. This study aims to develop and validate a numerical approach to estimate the GHA's wing cross-section in flight. The PARSEC method is combined with a scanned 3D point cloud of a dried GHA wing to create a 3D model and analyze an averaged aerofoil section. Using a pseudo-2D computational fluid dynamics model, the study explores passive morphing of bird wings due to aerodynamic pressure. Results show that the aerofoil morphs to achieve maximum potential aerodynamic efficiency at a Reynolds number of 2 × 105, decreasing in camber. The maximum lift-to-drag ratio ((/)max) increases from 3 to 44, primarily due to pressure drag reduction. However, the lack of comparison to true bird geometry in flight remains a limitation. Future research should compare the predicted morphing with actual bird specimens in flight. .},
}

@article {pmid39876791,
year = {2025},
author = {Ishimoto, K and Moreau, C and Herault, J},
title = {Robust undulatory locomotion through neuromechanical adjustments in a dissipative medium.},
journal = {Journal of the Royal Society, Interface},
volume = {22},
number = {222},
pages = {20240688},
pmid = {39876791},
issn = {1742-5662},
support = {//Fusion Oriented REsearch for disruptive Science and Technology/ ; //Japan Society for the Promotion of Science/ ; //Agence Nationale de la Recherche/ ; },
mesh = {Animals ; *Locomotion/physiology ; *Caenorhabditis elegans/physiology ; Models, Biological ; Swimming/physiology ; Models, Neurological ; Biomechanical Phenomena ; },
abstract = {Dissipative environments are ubiquitous in nature, from microscopic swimmers in low-Reynolds-number fluids to macroscopic animals in frictional media. In this study, we consider a mathematical model of a slender elastic locomotor with an internal rhythmic neural pattern generator to examine various undulatory locomotion such as Caenorhabditis elegans swimming and crawling behaviours. By using local mechanical load as mechanosensory feedback, we have found that undulatory locomotion robustly emerges in different rheological media. This progressive behaviour is then characterized as a global attractor through dynamical systems analysis with a Poincaré section. Furthermore, by controlling the mechanosensation, we were able to design the dynamical systems to manoeuvre with progressive, reverse and turning motions as well as apparently random, complex behaviours, reminiscent of those experimentally observed in C. elegans. The mechanisms found in this study, together with our dynamical systems methodology, are useful for deciphering complex animal adaptive behaviours and designing robots capable of locomotion in a wide range of dissipative environments.},
}

Animals
*Locomotion/physiology
*Caenorhabditis elegans/physiology
Models, Biological
Swimming/physiology
Models, Neurological
Biomechanical Phenomena

@article {pmid39865967,
year = {2025},
author = {Weihs, D and Farsani, A and Gurka, R},
title = {Towards a standard application of the Reynolds number in studies of aquatic animal locomotion.},
journal = {The Journal of experimental biology},
volume = {},
number = {},
pages = {},
doi = {10.1242/jeb.249896},
pmid = {39865967},
issn = {1477-9145},
abstract = {Nondimensional groups of measured quantities enable comparison between measurements of animals under different conditions and comparison between species. One of the most used such group is the Reynolds number, which compares inertial and viscous contributions to forces on swimming animals. This group includes two quantities that are chosen by the researcher: a typical length and speed. Choosing these parameters will affect the numerical value of the Reynolds number, defining the state of the fluid flow. For example: by choosing fish body length as opposed to propulsive fin chord, results may vary by an order of magnitude with consequences for analysis and hydrodynamic regimes. Here we suggest a standardized sets of lengths and speeds to be used for aquatic animal locomotion to enable confident utilization of data from different sources. This framework aims to improve comparative studies within the field.},
}

@article {pmid39860147,
year = {2025},
author = {Lim, HS and Choi, WI and Lim, JM},
title = {Continuous Production of Docetaxel-Loaded Nanostructured Lipid Carriers Using a Coaxial Turbulent Jet Mixer with Heating System.},
journal = {Molecules (Basel, Switzerland)},
volume = {30},
number = {2},
pages = {},
pmid = {39860147},
issn = {1420-3049},
support = {2023 Sabbatical Year//Soonchunhyang University/ ; NRF-2022R1C1C1007442//National Research Foundation of Korea/ ; 5199991614564//Ministry of Education/ ; 23C0113L1//Ministry of Science and ICT/ ; },
mesh = {*Drug Carriers/chemistry ; *Lipids/chemistry ; *Docetaxel/chemistry ; *Nanostructures/chemistry ; Nanoparticles/chemistry ; Particle Size ; Heating ; Antineoplastic Agents/chemistry/administration & dosage ; },
abstract = {The continuous synthesis of nanoparticles (NPs) has been actively studied due to its great potential to produce NPs with reproducible and controllable physicochemical properties. Here, we achieved the high throughput production of nanostructured lipid carriers (NLCs) using a coaxial turbulent jet mixer with an added heating system. This device, designed for the crossflow of precursor solution and non-solvent, combined with the heating system, efficiently dissolves solid lipids and surfactants. We reported the flow regime according to the Reynolds number (Re). Also, we confirmed the size controllability of NLCs as dependent on both Re and lipid concentration. The optimized synthesis yields NLCs around 80 nm, ideal for targeted drug delivery by enhanced permeability and retention (EPR) effect. The coaxial turbulent jet mixer enables effective mixing, producing uniform size distribution of NLCs. The NLCs prepared using the coaxial turbulent jet mixer were smaller, more uniform, and had higher drug loading compared to the NLCs synthesized by a bulk nanoprecipitation method, showcasing its potential for advancing nanomedicine.},
}

*Drug Carriers/chemistry
*Lipids/chemistry
*Docetaxel/chemistry
*Nanostructures/chemistry
Nanoparticles/chemistry
Particle Size
Heating
Antineoplastic Agents/chemistry/administration & dosage

@article {pmid39858737,
year = {2025},
author = {Waqas, M and Palevicius, A and Jurenas, V and Pilkauskas, K and Janusas, G},
title = {Design and Investigation of a Passive-Type Microfluidics Micromixer Integrated with an Archimedes Screw for Enhanced Mixing Performance.},
journal = {Micromachines},
volume = {16},
number = {1},
pages = {},
pmid = {39858737},
issn = {2072-666X},
abstract = {In recent years, microfluidics has emerged as an interdisciplinary field, receiving significant attention across various biomedical applications. Achieving a noticeable mixing of biofluids and biochemicals at laminar flow conditions is essential in numerous microfluidics systems. In this research work, a new kind of micromixer design integrated with an Archimedes screw is designed and investigated using numerical simulation and experimental approaches. First, the geometrical parameters such as screw length (l), screw pitch (p) and gap (s) are optimized using the Design of Expert (DoE) approach and the Central Composite Design (CCD) method. The experimental designs generated by DoE are then numerically simulated aiming to determine Mixing Index (MI) and Performance Index (PI). For this purpose, COMSOL Multiphysics with two physics modules-laminar and transport diluted species-is used. The results revealed a significant influence of screw length, screw pitch and gap on mixing performance. The optimal design achieved is then scaled up and fabricated using a 3D additive manufacturing technique. In addition, the optimal micromixer design is numerically and experimentally investigated at diverse Reynolds numbers, ranging from 2 to 16. The findings revealed the optimal geometrical parameters that produce the best result compared to other designs are a screw length of 0.5 mm, screw pitch of 0.23409 mm and a 0.004 mm gap. The obtained values of the mixing index and the performance index are 98.47% and 20.15 Pa[-1], respectively. In addition, a higher mixing performance is achieved at the lower Reynolds number of 2, while a lower mixing performance is observed at the higher Reynolds number of 16. This study can be very beneficial for understanding the impact of geometrical parameters and their interaction with mixing performance.},
}

@article {pmid39858707,
year = {2024},
author = {Demircali, AA and Yilmaz, A and Uvet, H},
title = {Enhanced Fluid Mixing in Microchannels Using Levitated Magnetic Microrobots: A Numerical Study.},
journal = {Micromachines},
volume = {16},
number = {1},
pages = {},
pmid = {39858707},
issn = {2072-666X},
support = {FBA-2022-5328//Council of Higher Education (YOK) of Turkey/ ; },
abstract = {The efficient mixing of fluids at microscale dimensions presents challenges due to the dominant laminar flow regime which restricts convective mixing. This study introduces a numerical analysis of a novel microrobotic mixing system with a levitated propeller robot, driven by magnetic fields, within a Y-shaped microchannel with a square cross-section (500 × 500 μm). Our research investigates the fluid mixing effectiveness facilitated by the microrobot through various levitation heights and orientations to enhance the mixing index (MI). This index is tested under different conditions by leveraging the dynamics of the propeller robot, characterized by adjustable roll and pitch angles and varying levitation heights. The numerical simulations, conducted using COMSOL[®] (Finite Element Method, FEM) software, integrate Maxwell's equations for magnetic field interaction with momentum and transport-diffusion equations to analyze fluid dynamics within the microchannel. Results indicate that the propeller robot can achieve an MI of up to 98.94% at a 150 μm levitation height and 1500 rpm propeller speed within 3 s. Additionally, the study examines the impact of propeller speed, Reynolds number, and robot length on mixing performance, providing comprehensive guidance for optimizing microscale fluid mixing in lab-on-a-chip applications.},
}

@article {pmid39848283,
year = {2025},
author = {Pal, TK and Das, S},
title = {Dynamics search of highly magnetized blood laden with copper-gold-titania nanoparticles in a ciliary artery with catheterization and entropy.},
journal = {Electromagnetic biology and medicine},
volume = {44},
number = {1},
pages = {26-64},
doi = {10.1080/15368378.2024.2443835},
pmid = {39848283},
issn = {1536-8386},
mesh = {*Copper/chemistry/pharmacology ; *Gold/chemistry/pharmacology ; *Entropy ; *Titanium/chemistry ; Hydrodynamics ; Metal Nanoparticles/chemistry ; Catheters ; Arteries/physiology ; Nanoparticles/chemistry ; },
abstract = {Biomagnetic fluid dynamics (BFD) is an emerging and promising field within fluid mechanics, focusing on the dynamics of bio-fluids like blood in the presence of magnetic fields. This research is crucial in the medical arena for applications such as medication delivery, diagnostic and therapeutic procedures, prevention of excessive bleeding, and treatment of malignant tumors using magnetic particles. This study delves into the intricacies of blood flow induced by cilia, carrying trihybrid nanoparticles (gold, copper, and titania), within a catheterized arterial annulus under a robust magnetic field. The model incorporates factors like Hall and ion-slip currents (electromagnetic effects on charged particles), metachronal propulsion (movement of cilia for propulsion), viscous dissipation, and entropy. The physical equations in the model are transformed from the laboratory frame to a wave frame and then simplified using conditions like low Reynolds number and long wavelength. Optimal series solutions are obtained through the homotopy perturbation method (HPM). The research explores how various physical parameters shape the bloodstream's features, presenting and analyzing these visually. A notable finding is that an intensification in Hall and ion-slip parameters results in higher blood velocity within the catheterized annulus. Blood cooling is observed with a higher loading of suspended nanoparticles. Entropy generation increases with growing values of Hall and ion-slip parameters, while the reverse trend is noted for the Bejan number. The wall shearing stress (WSS) reduces by 2.84% for 1% increase in Hall parameter. The study also provides a brief overview of how blood boluses (or clumps of blood) are structured under the influence of operating parameters. The modified hybrid nano-blood (MHNB) forms smaller and fewer boluses compared to pure blood (PB). Additionally, longer cilia length results in enhanced trapping of boluses due to stronger recovery motions of the cilia. This research holds potential benefits for practitioners and researchers in diagnosing and assessing conditions such as coronary artery disease, valvular heart disease, and congenital heart abnormalities, as well as for understanding traumatic brain injury and neurological surgeries.},
}

*Copper/chemistry/pharmacology
*Gold/chemistry/pharmacology
*Entropy
*Titanium/chemistry
Hydrodynamics
Metal Nanoparticles/chemistry
Catheters
Arteries/physiology
Nanoparticles/chemistry

@article {pmid39834443,
year = {2025},
author = {Zohora, FT and Haque, MR and Chowdhury, NM and Fahad, MK and Ifraj, NF},
title = {Optimization of hydrothermal performance in industrial heat sinks with innovative perforated pin fin designs: A numerical approach.},
journal = {Heliyon},
volume = {11},
number = {1},
pages = {e41496},
pmid = {39834443},
issn = {2405-8440},
abstract = {This study emphasizes the importance of optimizing pin-finned heat sinks as a means of addressing thermal engineering issues. It aims to investigate the use of perforations and unique fin designs in relation to staggered pin arrays in order to fill a gap in existing research. Three-dimensional incompressible flow simulation is performed with the Fluent software. Modeling turbulence is accomplished by employing the realizable κ-ε models, while the numerical solution of all equations pertaining to fluid flow is carried out with the proper boundary conditions. In order to make a comparison of geometry, the hydrothermal performance factor (HTPF) is utilized for Reynolds number (Re) values ranging from 8500 to 44,502. Using a Re of 44502, the Nusselt number (Nu) was found to be raised by 66.2 % for spherical cube pin fins with hexagonal perforation and 70.2 % for elliptical perforation, respectively. A reduction of about 17.6 % in the pressure drop was seen when compared with an elliptical perforated infinity loop design, which resulted in a higher hydrothermal performance factor (HTPF) that was 70 % higher than that of the cylindrical case. Furthermore, the copper-diamond composite, which was placed on an infinity loop-shaped pin fin and had elliptical perforations, yielded a 144 % increase in HTPF when the Re is 44502. Taking into account this fact, it can be concluded that the designs that have been offered are ideal for a wide variety of industrial applications that aim to significantly enhance thermal potential.},
}

@article {pmid39816520,
year = {2025},
author = {Dinesh Kumar, M and Díaz Palencia, JL and Dharmaiah, G and Wakif, A and Noeiaghdam, S and Fernandez-Gamiz, U and Dinarvand, S},
title = {ANFIS-PSO analysis on axisymmetric tetra hybrid nanofluid flow of Cu-CNT-Graphene-Tio2 with WEG-Blood under linear thermal radiation and inclined magnetic field: A bio-medicine application.},
journal = {Heliyon},
volume = {11},
number = {1},
pages = {e41429},
pmid = {39816520},
issn = {2405-8440},
abstract = {BACKGROUND: The development of heat transfer devices used for heat conversion and recovery in several industrial and residential applications has long focused on improving heat transfer between two parallel plates. Numerous articles have examined the relevance of enhancing thermal performance for the system's performance and economics. Heat transport is improved by increasing the Reynolds number as the turbulent effects grow.

APPLICATIONS: Regarding heat transfer, hybrid nanofluids are superior to mono nanofluids. The hybrid fluid of Cu-CNT + Graphene + TiO2/WEG-Blood, which is subject to heat transfer in a channel between two parallel plates with an angled magnetic field and linear thermal radiation, has numerous applications in engineering, industry, and biomedical research, such as electronic cooling, drug delivery, cancer treatment, optics, missiles, satellites, transformer-electronic cooling, and military solar-equipment.

OBJECTIVE: Examining the qualities of mass, flow, and heat transmission is the aim of the study of a hybrid Cu-CNT- Graphene-TiO2/WEG-Blood nanofluid as it moves via a tube of porous material that is exposed to linear thermal radiation, inclined magnetic, Forchheimer, and buoyancy influences. ANFIS-PSO model is assumed.

METHOD: Applying the ODE45 integration technique to the given numerical solutions yields non-linear, non-dimensionalized, and highly partial differential equations that control the momentum, energy, and concentration. Consequently, the numerical simulation shows the concentration, velocity, and temperature profiles of the hybrid Cu-CNT- Graphene-TiO2/WEG-Blood nanofluid. A strong concordance is noted between recent and past results.

Radiation regulates the microchannel temperature distribution, which significantly contributes to cooling the flow transport system, and the thermal radiation parameter shows that radiation has a retarding influence on the temperature profile.},
}

@article {pmid39787163,
year = {2025},
author = {Mal, B and Dolui, S and Bhaumik, B and De, S},
title = {Impacts of variable magnetic field on ternary Casson nanofluid flow through ciliated arterial walls incorporating interfacial nanolayer.},
journal = {Electromagnetic biology and medicine},
volume = {44},
number = {1},
pages = {79-106},
doi = {10.1080/15368378.2024.2446506},
pmid = {39787163},
issn = {1536-8386},
mesh = {*Magnetic Fields ; *Hydrodynamics ; *Arteries/physiology ; Cilia/physiology ; Humans ; Rheology ; Nanoparticles/chemistry ; Nanotechnology ; },
abstract = {The current investigation explores tri-hybrid mediated blood flow through a ciliary annular model, designed to emulate an endoscopic environment. The human circulatory system, driven by the metachronal ciliary waves, is examined in this study to understand how ternary nanoparticles influence wave-like flow dynamics in the presence of interfacial nanolayers. We also analyze the effect of an induced magnetic field on Ag-Cu-Al2O3/blood flow within the annulus, focusing on thermal radiation, heat sources, buoyancy forces and ciliary motion. The Casson fluid model characterizes the non-Newtonian viscous properties of the biofluid. To describe the steady fluid flow mathematically, we use coupled partial differential equations and apply the homotopy perturbation method to derive rapidly convergent series solutions for the non-linear flow equations. The obtained hemodynamic consequences are graphically represented with the variations of emerging parameters. These are significantly influenced by the rheological factors of the nanofluid flow, improving flow velocity with changes in shear viscosity, while a decrease in flow is observed for intensified Lorentz forces. Ciliary motion accelerates the expansion of the induced magnetic field on nanolayers, while a higher Magnetic Reynolds number decreases the current density distribution. Increased radiative heat generation lowers the temperature, indicating that thermal radiation enhances heat transfer and improves cooling efficiency. In contrast, an increased ciliary length along the wall raises the temperature due to wave-like motion, which strengthens the thermal boundary layer in the fluid flow. Additionally, a higher nanoparticle concentration increases wall shear stress due to frictional forces, while enhanced magnetic forces decrease the shear stress along the ciliary wall. Furthermore, a higher Strommer's number may regulate the formation of blood boluses in the wavy flow. The key findings play an important role in the development of analytical benchmarks to validate computational methods, ensuring accuracy in clinical research tools and supporting reliable medical applications.},
}

*Magnetic Fields
*Hydrodynamics
*Arteries/physiology
Cilia/physiology
Humans
Rheology
Nanoparticles/chemistry
Nanotechnology

@article {pmid39786510,
year = {2025},
author = {Deymi, P and Karimi, H and Sharififard, H and Salehi, F},
title = {Simulation of solar photocatalytic reactor with immobilized photocatalyst for degradation of pharmaceutical pollutants.},
journal = {Environmental science and pollution research international},
volume = {},
number = {},
pages = {},
pmid = {39786510},
issn = {1614-7499},
abstract = {This study focuses on the simulation of a solar photocatalytic reactor with linear parabolic reflectors and continuous fluid flow. The simulation approach was initially validated against experimental data reported by Miranda-Garcia et al. Catal Today 151:107-113 (2010), yielding a high degree of accuracy of approximately 0.99%. In this article, the effect of light intensity, Reynolds number, and fluid residence time on the performance of a photoreactor system using titanium dioxide catalyst and ibuprofen pollutant has been investigated. The results show that the intensity of light intensity has an effect of up to 29% on the decomposition of pollutant. With the increase of radiation intensity, the removal of pollutants reached from 85.5% to 99.46%. It has been demonstrated that higher flow turbulence significantly impacts removal efficiency, achieving rates of up to 71%. Moreover, enhancing the fluid's residence time through implementing a recirculating flow within the photoreactor has resulted in a 13% enhancement in removal efficiency. These results can be an important guide for optimizing the design of photocatalytic reactors. By adjusting the examined parameters, it is possible to obtain a higher efficiency in the removal of pollutants, which will be very effective in the scaling and industrial design of solar reactors.},
}

@article {pmid39769641,
year = {2024},
author = {Dutkowski, K and Kruzel, M and Kochanowska, M},
title = {Transition Boundary from Laminar to Turbulent Flow of Microencapsulated Phase Change Material Slurry-Experimental Results.},
journal = {Materials (Basel, Switzerland)},
volume = {17},
number = {24},
pages = {},
pmid = {39769641},
issn = {1996-1944},
abstract = {An ice slurry or an emulsion of a phase change material (PCM) is a multiphase working fluid from the so-called Latent Functional Thermal Fluid (LFTF) group. LFTF is a fluid that uses, in addition to specific heat, the specific enthalpy of the phase change of its components to transfer heat. Another fluid type has joined the LFTF group: a slurry of encapsulated phase change material (PCM). Technological progress has made it possible for the phase change material to be enclosed in a capsule of the size of the order of micrometers (microencapsulated PCM-mPCM) or nanometers (nanoencapsulated PCM-nPCM). This paper describes a method for determining the Reynolds number (Re) at which the nature of the flow of the mPCM slurry inside a straight pipe changes. In addition, the study results of the effect of the concentration of mPCM in the slurry and the state of the PCM inside the microcapsule on the value of the critical Reynolds number (Recr) are presented. The aqueous slurry of mPCM with a concentration from 4.30% to 17.20% wt. flowed through a channel with an internal diameter of d = 4 mm with a flow rate of up to 110 kg/h (Re = 11,250). The main peak melting temperature of the microencapsulated paraffin wax used in the experiments was around 24 °C. The slurry temperature during the tests was maintained at a constant level. It was 7 °C, 24 °C and 44 °C (the PCM in the microcapsule was, respectively, a solid, underwent a phase change and was a liquid). The experimental studies clearly show that the concentration of microcapsules in the slurry and the state of the PCM in the microcapsule affect the critical Reynolds number. The higher the concentration of microcapsules in the slurry, the more difficult it was to maintain laminar fluid flow inside the channel. Furthermore, the laminar flow of the slurry terminated at a lower critical Reynolds number when the PCM in the microcapsule was solid. Caution is advised when choosing the relationship to calculate the flow resistance or heat transfer coefficients, because assuming that the flow motion changes at Re = 2300, as in the case of pure liquids, may be an incorrect assumption.},
}

@article {pmid39766673,
year = {2024},
author = {Heinz, S},
title = {Physically Consistent Resolving Simulations of Turbulent Flows.},
journal = {Entropy (Basel, Switzerland)},
volume = {26},
number = {12},
pages = {},
pmid = {39766673},
issn = {1099-4300},
abstract = {Usually applied simulation methods for turbulent flows as large eddy simulation (LES), wall-modeled LES (WMLES), and detached eddy simulation (DES) face significant challenges: they are characterized by improper resolution variations and essential practical simulation problems given by huge computational cost, imbalanced resolution transitions, and resolution mismatch. Alternative simulation methods are described here. By using an extremal entropy analysis, it is shown how minimal error simulation methods can be designed. It is shown that these methods can overcome the typical shortcomings of usually applied simulation methods. A crucial ingredient of this analysis is the identification of a mathematically implied general hybridization mechanism, which is missing in existing methods. Applications to several complex high Reynolds number flow simulations reveal essential performance, functionality, and computational cost advantages of minimal error simulation methods.},
}

@article {pmid39756050,
year = {2025},
author = {Hernández-Melchor, DJ and López-Pérez, PA and Ferrera-Cerrato, R and Alarcón, A},
title = {Study of the hydrodynamic parameters in an internal flat-plate airlift reactor for the increased degradation of newspaper by Trichoderma reesei.},
journal = {Environmental technology},
volume = {},
number = {},
pages = {1-16},
doi = {10.1080/09593330.2024.2447959},
pmid = {39756050},
issn = {1479-487X},
abstract = {The aim of our study was to characterize the hydrodynamics and mass transfer in a novel internal flat-plate airlift cylindrical reactor to increase the biodegradation of newspaper. We evaluated the degradation kinetics of newspaper in a batch culture with Trichoderma reesei. Gas holdup, mixing time, the Reynolds number, and volumetric mass transfer coefficient (kLa) properties were characterized in biphasic and triphasic systems in order to optimize their operational conditions. An analysis of two effective factors in three levels including kLa, and Reynolds number (Re) were optimized by a full factorial design. Furthermore, a follow-up analysis of the ANOVA results p ≤ 0.05 was performed using Tukey's rank test method for p-value corrections. The overall kLa (triphasic system) was calculated to be between 2.34 and 14.76 h[-1] with an optimal value of 8.0 h[-1] (Flow: 3 L min[-1]) and a Re of 1757. In addition, to show the optimal conditions, kinetic experiments were developed for 20 days using newspaper as carbon source for quantified the enzyme activities, biomass, residual cellulose, and reducing sugars 1421 IU L[-1] CMCase, 8.02, 2.19, and 0.07 g L[-1], respectively. The degradation rate of newspaper was over 80%, which was significantly higher than that of the nominal value. Finally, the theoretical correlation proposed for kLa was compared and estimated with respect to the experimental values with an error of ±20%. The kLa and the Re are important criteria in assessing an optimal degradation of newspaper in an industrial process scale-up.},
}

@article {pmid39738111,
year = {2024},
author = {Rao, Y and Wang, Y and Wang, S and Gong, Z and Zhang, C},
title = {Numerical simulation study on the influence of bend diameter rate on the flow characteristics of nature gas hydrate particles.},
journal = {Scientific reports},
volume = {14},
number = {1},
pages = {31604},
pmid = {39738111},
issn = {2045-2322},
support = {BE2022001-5//Project of Emission Peak and Carbon Neutrality of Jiangsu Province/ ; BE2022001-5//Project of Emission Peak and Carbon Neutrality of Jiangsu Province/ ; 2022N045//Quanzhou Science and Technology Planning Project/ ; 2022N045//Quanzhou Science and Technology Planning Project/ ; KYCX24_3245 and SJCX24_1682//Jiangsu Provincial Graduate Research and Innovation Program Project/ ; KYCX24_3245 and SJCX24_1682//Jiangsu Provincial Graduate Research and Innovation Program Project/ ; },
abstract = {Bend pipe is a common part of long distance pipeline. There is very important to study the flow law of hydrate particles in the bend pipe, and pipeline design will be optimized. In addition, the efficiency and safety of pipeline gas transmission will be improved. With the flow of hydrate particles in a curved pipe as the object of study, the effects of Bend diameter rate and Reynolds number on the velocity distribution, turbulent kinetic energy change, wall shear force, particle motion and pressure drop distribution of the spiral flow carrying hydrate particles were investigated by numerical simulation method. The results show that bend diameter rate is the smaller, and the high speed zone is easier to appear inside the bend. Moreover, the uniformity of the velocity distribution of the fluid flowing through the bend is slower with the smaller the rate of the bend to the diameter. When Re = 20,000, the curve fluctuates more, and the peak speed reaches 4 times that of Re = 10,000. Increasing the Reynolds number of the initial transport can maintain the helical flow strength of the fluid after passing through the bend pipe, so that the flow can obtain higher tangential force. Because the fluid flows into the pipe by spiral flow, the shear force inside the pipe is higher under the combined action of its tangential velocity at the pipe wall and the high speed zone inside the pipe wall. The presence of the twisted tape leads to greater flow resistance, which makes the pressure drop increase at the position of the twisted tape different. At the same position, the Reynolds number is larger, and the pressure drop increases larger, and the Bend diameter rate is larger, and the fluid speed recovers faster, and the velocity is smaller, and the unit pressure drop is smaller, and Unit pressure drop is down 72.9%. The increase of Reynolds number can reduce the resistance coefficient of the Bend part, but the increase of the Bend diameter rate makes the resistance coefficient decrease first and then increase.},
}

@article {pmid39732920,
year = {2024},
author = {Žáček, J and Strecker, Z and Jeniš, F and Macháček, O and Goldasz, J and Sapinski, B and Vrbka, M and Kubík, M},
title = {Impact of magnetorheological fluid composition on their behaviour in gradient pinch mode.},
journal = {Scientific reports},
volume = {14},
number = {1},
pages = {31320},
pmid = {39732920},
issn = {2045-2322},
support = {GACR 21-45236L//Grantová Agentura České republiky-GACR/ ; GACR 21-45236L//Grantová Agentura České republiky-GACR/ ; GACR 21-45236L//Grantová Agentura České republiky-GACR/ ; GACR 21-45236L//Grantová Agentura České republiky-GACR/ ; GACR 21-45236L//Grantová Agentura České republiky-GACR/ ; GACR 21-45236L//Grantová Agentura České republiky-GACR/ ; 2020/39/I/ST8/02916//Narodowe Centrum Nauki-NCN/ ; 2020/39/I/ST8/02916//Narodowe Centrum Nauki-NCN/ ; },
abstract = {Magnetorheological (MR) fluids can be utilized in one of the fundamental operating modes of which the gradient pinch mode has been the least explored. In this unique mode non-uniform magnetic field distributions are taken advantage of to develop a so-called Venturi-like contraction in MR fluids. By adequately directing magnetic flux the material can be made solidified in the regions near the flow channel wall, thus creating a passage in the middle of the channel for the fluid to pass through. This leads to unique variations of the slope in the pressure-flow rate characteristics. It can be stated that the effect of the MR fluid composition on the behaviour of the MR fluid in gradient pinch mode has not been thoroughly investigated yet. In this study, the behaviour of MR fluids was assessed with a dedicated pinch mode MR valve that provided a valuable insight into the contraction mechanism using fluorescence microscopy. Briefly, seven MR fluid samples were prepared with different particle concentrations (10%, 22% and 32 vol%) and mean particle sizes (2, 4.5 and 8.2 μm). It was found that the MR fluid sample with the larger particle size exhibits a significantly larger slope change observed in the pressure-flow rate characteristics. Increasing the particle size from 2 μm (base) to 8 μm resulted in the slope increase by a factor of 2.6 compared to the base sample. Increasing the particle concentration has a negligible effect on the pinch mode effect. Finally, these results were analysed using the modified Wuest equation, which is commonly used for characterizing sharp-edged orifices in low Reynolds number flow regimes. The simple equation was determined to describe the behaviour of MR fluids in gradient pinch mode with adequate accuracy.},
}

@article {pmid39730787,
year = {2024},
author = {Wei, T and Wang, C and Zhao, Y and Shen, M and Chen, Z},
title = {Numerical study on the evolution characteristics of contact and fluid flow in shear-induced rough joint.},
journal = {Scientific reports},
volume = {14},
number = {1},
pages = {30971},
doi = {10.1038/s41598-024-82008-3},
pmid = {39730787},
issn = {2045-2322},
support = {52364004//National Natural Science Foundation of China/ ; },
abstract = {In order to investigate the influence of shear on contact characteristics and fluid flow evolution of rough rock fractures, a series of shear-flow tests were carried out by numerical experiments. Firstly, a sandstone specimen with a rough fracture was made in the laboratory, and the numerical model of the fracture was reconstructed in FLAC3D software. Experiments were conducted to investigate the depth of penetration of the fracture under different normal stress (1, 3, and 5 MPa) and shear displacement (2, 4, 6, 8, and 10 mm). By establishing the relationship between the shear direction and the apparent inclination of the fracture asperity, the effects on the asperity contact characteristics and seepage properties are explored. The results of the study indicated that the larger the normal stress the larger the surface contact section and the smaller the aperture, showing the opposite trend with increasing shear displacement. Positive apparent inclination distribution can effectively predict the location of shear damage during the shear process. Negative apparent dip implies that those regions increase permeability after shear, and decrease with increasing crack opening. Fracture seepage shows obvious nonlinear characteristics, where the nonlinear coefficients are 5-6 orders of magnitude larger than the linear coefficients. The critical Reynolds number Rec is used to distinguish the linear and nonlinear categories of fluid flow, and the calculated results show that the range of Rec is between 0.0081 and 0.11.3, and the Rec increases with shear displacement and decreases with normal stress.},
}

@article {pmid39722445,
year = {2025},
author = {Zhang, M and Tu, C and Guo, L and Hou, L and Li, Y and Du, P and Chen, J and Lin, J and Bao, F},
title = {Spontaneous Cargo Transport via Sliding Bubbles on a Superhydrophobic Wire.},
journal = {Langmuir : the ACS journal of surfaces and colloids},
volume = {41},
number = {1},
pages = {1175-1181},
doi = {10.1021/acs.langmuir.4c04539},
pmid = {39722445},
issn = {1520-5827},
abstract = {The transportation and carrying behavior of underwater bubbles have been widely used for an underwater microactuator, cargo displacement assembly, and drug delivery. This study explores a method for underwater cargo transportation using sliding bubbles as a vehicle with directionally guided superhydrophobic wires. By exploitation of the adhesion between superhydrophobic surfaces and bubble interfaces, a bubble is able to transport a superhydrophobic O-ring along a superhydrophobic wire, effectively delivering the O-ring to the water surface. The capability of the bubble-driven O-ring to rise along superhydrophobic wires was systematically evaluated and analyzed, focusing on the two configurations formed by the bubbles and O-rings. Additionally, we identified the conditions necessary for the successful rising of bubbles and O-rings of varying sizes as well as their trajectories and rising velocities. Through an analysis of the relationship between the Ohnesorge number and Reynolds number, the kinetic characteristics of the bubble-carrying O-ring are elucidated. Furthermore, the applications of bubble transportation in cyclic actuation and underwater data collection are substantiated. This strategy offers a highly reliable method for underwater information transmission and patrol as well as potential applications in bubble transportation.},
}

@article {pmid39708495,
year = {2025},
author = {Aghaee, A and Khan, MO},
title = {Pinning down the accuracy of physics-informed neural networks under laminar and turbulent-like aortic blood flow conditions.},
journal = {Computers in biology and medicine},
volume = {185},
number = {},
pages = {109528},
doi = {10.1016/j.compbiomed.2024.109528},
pmid = {39708495},
issn = {1879-0534},
mesh = {Humans ; *Neural Networks, Computer ; *Models, Cardiovascular ; Blood Flow Velocity/physiology ; Aorta/physiopathology ; Aortic Coarctation/physiopathology/diagnostic imaging ; Computer Simulation ; },
abstract = {BACKGROUND: Physics-informed neural networks (PINNs) are increasingly being used to model cardiovascular blood flow. The accuracy of PINNs is dependent on flow complexity and could deteriorate in the presence of highly-dynamical blood flow conditions, but the extent of this relationship is currently unknown. Therefore, we investigated the accuracy and performance of PINNs under a range of blood flow conditions, from laminar to turbulent-like flows.

METHODS: A stenosis was virtually induced in the thoracic segment of a patient's aorta to represent aortic coarctation. Stenosis severity was varied from 0% to 70% in increments of 5% (NCFD=15 cases), corresponding to stenotic Reynolds number that ranged from 1000 to 3333. CFD simulations at high spatial and temporal resolutions (6.9 million mesh, 10,000 time-steps) were performed for all NCFD=15 cases to obtain ground-truth velocity data. Fourier-based activation function in feed-forward PINNs with dynamic loss coefficients were trained to reconstruct CFD velocity field. Losses included those from physical equations, boundary conditions and sensor data sampled evenly from CFD simulations. Number of sensor points were increased from 200-1600 in increments of 200. This resulted in a total of 8 sensor point variations for each stenotic model (Nsens=8). Hence, a total of 120 (NCFDxNsens) cases were trained in this study. The PINNs architecture and data have been made open-sourced.

RESULTS: PINNs errors increased substantially for stenosis severity >50% (stenotic Reynolds numer > 2000) due to the presence of complex turbulent-like flow features. When using 400 sensor points, PINNs velocity magnitude errors ranged from 30% for no-stenosis model to 57% for the model with 70% stenosis, and dropped to 10% and 20%, respectively when the number of sensor points were increased to 1600. PINNs velocity magnitude errors increased monotonically with turbulent intensity, particularly beyond stenosis severity of 50%.

CONCLUSIONS: Our findings indicate that the accuracy of PINNs is dependent on the complexity of blood flow conditions. Using conventional PINNs architecture, the errors in trained velocity can increase substantially in the presence of turbulent-like blood flows that are typically found in various vascular pathologies.},
}

Humans
*Neural Networks, Computer
*Models, Cardiovascular
Blood Flow Velocity/physiology
Aorta/physiopathology
Aortic Coarctation/physiopathology/diagnostic imaging
Computer Simulation

@article {pmid39703560,
year = {2024},
author = {Chen, J and Hu, W and Dong, X and Lin, J and Gao, Z and Qiu, B},
title = {Experimental investigation on modes of spray formation, droplet size and size distribution in a spinning disc atomizer.},
journal = {Frontiers in plant science},
volume = {15},
number = {},
pages = {1470745},
pmid = {39703560},
issn = {1664-462X},
abstract = {The spinning disc atomizer is extensively utilized in agricultural spraying, with optimized operating conditions significantly enhancing atomization performance. In this paper, the atomization characteristics of a spinning disc were studied using photographs taken by a high-speed camera. Ethanol-water solutions were used at various flow rates and the disc speed was varied in a wide range. The influence of disc speed, flow rate, and surface tension on modes of spray formation, droplet size, and size distribution were investigated. The correlations for Reynolds number (Re), Stability number (St), and dimensionless droplet size (d[*]) were proposed in a wide range of operational conditions. The Rosin-Rammler (RR) and modified Rosin-Rammler (MRR) distributions appropriately represented the droplet size distribution. It was found that the increase in flow rate resulted in modes of spray formation translation under the same disc speed and ethanol-water solution. The predicted droplet sizes showed good agreement with the experiment values. Most of the predicted droplet sizes were within the band of ±15% of the experiment values. The droplet size decreased with increasing Re or St, but was hardly affected by q. Besides, the droplet size decreased with increasing disc speed and decreasing surface tension. The RR and MRR distribution matched with the calculated cumulative volume fraction from the experimental data reasonably well for the entire range. It was recommended to appropriately elevate Re during the spinning disc atomization process to narrow the range of droplet sizes and enhance uniformity.},
}

@article {pmid39687179,
year = {2024},
author = {Harahap, MG and Abfertiawan, MS and Syafila, M and Handajani, M and Gultom, TH},
title = {Electrocoagulation for nickel, chromium, and iron removal from mine water using aluminum electrodes.},
journal = {Heliyon},
volume = {10},
number = {23},
pages = {e40784},
pmid = {39687179},
issn = {2405-8440},
abstract = {High global demand for nickel metal has contributed significantly to the growth of the nickel mining industry in Indonesia. This growth has a positive multiplier effect on the economy, with the potential to affect aquatic life and humans owing to the high levels of chromium, nickel, and iron in mine water. Therefore, this study aims to develop an electrocoagulation (EC) reactor to remove nickel, chromium, and iron from mine water. This study used a continuous reactor and aluminum electrodes with variations in current density (3.378, 6.757, and 10.135 mA/cm[2]) and inflow (0.3, 0.5, and 1 L/min). The results showed that the operating scenario with a current strength of 6 A and an inflow of 0.3 L/min had a removal efficiency of 86.89 % nickel, 99.51 % chromium, and 80.61 % iron with a charge loading value of 11,194 F/ma[3] and Reynolds number of 39. These results are expected to provide valuable information for the development of an effective EC technology, thereby demonstrating its potential for the removal of metals from nickel mine water.},
}

@article {pmid39679780,
year = {2024},
author = {Song, Y and Ming, P and Xun, B},
title = {Research on similarity law of the flow-induced noise of the submarine.},
journal = {The Journal of the Acoustical Society of America},
volume = {156},
number = {6},
pages = {4010-4023},
doi = {10.1121/10.0034606},
pmid = {39679780},
issn = {1520-8524},
abstract = {Flow-induced noise is a complex source that significantly impacts submarines' stealth performance. While previous studies have provided valuable insights into the acoustic radiation of scaled-down submarine models, addressing the flow noise of full-scale prototypes has remained a daunting challenge. To bridge this gap, the research team undertook an extensive investigation to unveil the elusive similarity law of flow noise in both small and large-scale submarine models. By leveraging computational algorithms and turbulence models, the flow field of the submarine model was simulated, and the Kirchhoff and Ffowcs Williams-Hawkings model was employed to calculate the submarine's flow noise. This comprehensive study meticulously considered various influential factors, including Mach number, Reynolds number, etc., ultimately formulating a similarity correlation formula for submarine flow noise. The findings of this study revealed several key insights, including the minimal impact of accessories on submarine flow noise similarity, the adherence of the frequency of submarine flow noise to the Helmholtz number, and the intricate relationship between sound pressure level similarity law with Mach and Reynolds number. Ultimately, this study introduces and summarizes the submarine flow noise similarity law. This law enables the estimation of real-scale model flow noise by using small-scale model flow noise as a reference.},
}

@article {pmid39677972,
year = {2024},
author = {Rosafio, N and Salvadori, S and Misul, DA},
title = {Implementation of a high-order spatial discretization into a finite volume solver: Applications to turbomachinery test cases using an eddy-viscosity turbulence closure.},
journal = {Heliyon},
volume = {10},
number = {16},
pages = {e36478},
pmid = {39677972},
issn = {2405-8440},
abstract = {In this study, the implementation of a high-order spatial discretization method into a Finite Volume solver is presented. Specific emphasis is put on the analysis of the performance over selected turbomachinery test cases. High-order numerical discretization is achieved by adopting the cell-centered Least-Square reconstruction, which is implemented in the in-house solver HybFlow. The validation of the adopted methodology is performed by assessing the solution of a turbulent flat plate with zero pressure gradient, using a eddy-viscosity transitional model. The test case also evidences the effect of the discretization of gradient-based source terms when a high-order reconstruction methodology is used. In the second part of the paper, the solver is used for the solution of relevant two-dimensional turbomachinery test cases, assessing the impact of 2 n d and 3 r d order reconstruction on the prediction of the aerodynamics and the heat transfer for respectively a low-pressure blade and a high-pressure turbine vane. It is shown how a high-order reconstruction allows for obtaining a better prediction of turbomachinery aerodynamics, with lower number of elements. The benefits over heat transfer predictions in high Reynolds number conditions are instead limited to the reduction of heat transfer coefficient spikes in under-resolved regions of the blade. Eventually, the methodology is validated for a three-dimensional low-pressure turbine cascade with realistic boundary layer inflow conditions.},
}

@article {pmid39657794,
year = {2024},
author = {Yoshizawa, K and Motani, R},
title = {Waveform geometry dictating optimal cruising in animals.},
journal = {Journal of the Royal Society, Interface},
volume = {21},
number = {221},
pages = {20240442},
pmid = {39657794},
issn = {1742-5662},
support = {//Japan Society for the Promotion of Science/ ; },
mesh = {Animals ; *Swimming/physiology ; *Models, Biological ; *Fishes/physiology ; Biomechanical Phenomena ; },
abstract = {For sustained swimming and flights, vertebrates and insects oscillate their propulsors periodically within a narrow range of Strouhal number (St), a dimensionless quantity describing the rate and density of the motion, suggesting a close relationship between the range and cruising optimality. The persistence of this range across size and fluids has puzzled biologists and engineers, resulting in multiple interpretations of its cause. Here, we propose that the optimal St range is largely constrained by power output efficiency of the trailing edge of the caudal fin. A mathematical model of the periodic wake of the trailing edge, which defines the proportion of power lost without contributing to propulsion, predicts that such energy loss is minimal in the observed range of St preferred by fish. The constraints apply across a range of Reynolds number in cruising fish. The same constraints dictate the optimal speed across a wide range of swimmers, in combination with morphological characteristics. Other factors such as drag properties also affect the optimal swimming speed, but probably to a smaller extent. The result that the geometry of periodic waveforms is key to cruising optimality provides an additional angle to study animal locomotion in fluids and related bioinspired robotics.},
}

Animals
*Swimming/physiology
*Models, Biological
*Fishes/physiology
Biomechanical Phenomena

@article {pmid39636852,
year = {2024},
author = {Chen, MA and Lee, SH and Kang, PK},
title = {Inertia-induced mixing and reaction maximization in laminar porous media flows.},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
volume = {121},
number = {50},
pages = {e2407145121},
pmid = {39636852},
issn = {1091-6490},
support = {DE-SC0023429//U.S. Department of Energy (DOE)/ ; EAR-1952686//NSF (NSF)/ ; EAR-2046015//NSF (NSF)/ ; },
abstract = {Solute transport and biogeochemical reactions in porous and fractured media flows are controlled by mixing, as are subsurface engineering operations such as contaminant remediation, geothermal energy production, and carbon sequestration. Porous media flows are generally regarded as slow, so the effects of fluid inertia on mixing and reaction are typically ignored. Here, we demonstrate through microfluidic experiments and numerical simulations of mixing-induced reaction that inertial recirculating flows readily emerge in laminar porous media flows and dramatically alter mixing and reaction dynamics. An optimal Reynolds number that maximizes the reaction rate is observed for individual pore throats of different sizes. This reaction maximization is attributed to the effects of recirculation flows on reactant availability, mixing, and reaction completion, which depend on the topology of recirculation relative to the boundary of the reactants or mixing interface. Recirculation enhances mixing and reactant availability, but a further increase in flow velocity reduces the residence time in recirculation, leading to a decrease in reaction rate. The reaction maximization is also confirmed in a flow channel with grain inclusions and randomized porous media. Interestingly, the domain-wide reaction rate shows a dramatic increase with increasing Re in the randomized porous media case. This is because fluid inertia induces complex three-dimensional flows in randomized porous media, which significantly increases transverse spreading and mixing. This study shows how inertial flows control reaction dynamics at the pore scale and beyond, thus having major implications for a wide range of environmental systems.},
}

@article {pmid39632088,
year = {2024},
author = {Zhu, W and Shen, Y and Jia, Y and Dai, X and Liu, S and Lin, Y and Xu, Y},
title = {Gradient Nonwettability Controls Water-Film Flowing Features.},
journal = {Langmuir : the ACS journal of surfaces and colloids},
volume = {40},
number = {50},
pages = {26487-26499},
doi = {10.1021/acs.langmuir.4c03243},
pmid = {39632088},
issn = {1520-5827},
abstract = {The flow of the water film on solid surface depended on the film Reynolds number and wind speed. Moreover, environmental factors had an impact on the flow process. This study explored how surface wettability impacts the stability and detachment of water film under varying conditions. Superhydrophobic surface played a critical role in speeding up the detachment of water film, especially under conditions of strong wind and specific flow dynamics, such as a wind speed of 19 m/s and a Reynolds number of 83. The efficiency in water removal was due to a combination of forces: capillary action, which pulls the water into smaller areas, reduced surface tension, and decreased adhesion between the liquid and surface. These factors worked together to shrink the area of contact, allowing the film to break and detach more easily. The findings suggested that enhancing nonwettability can improve water removal efficiency, with potential applications in fields like aerospace. Furthermore, additional trials across varying wind speeds and Reynolds numbers consistently supported the superior performance of superhydrophobic surface in driving rapid water-film detachment. To advance this effect, a gradient nonwetting surface was introduced, specifically engineered within the superhydrophobic regime, to amplify the velocity of film separation. This design innovation leveraged variations in surface energy across the gradient, which fostered directional water-film movement and accelerated detachment. A comprehensive analysis of the underlying physical mechanisms further elucidated its potential in enhancing water-shedding applications across a range of environmental conditions.},
}

@article {pmid39626617,
year = {2024},
author = {Ahnn, S and Kim, H and Choi, H},
title = {Aerodynamic performance enhancement of a vertical-axis wind turbine by a biomimetic flap.},
journal = {Bioinspiration & biomimetics},
volume = {20},
number = {1},
pages = {},
doi = {10.1088/1748-3190/ad9a45},
pmid = {39626617},
issn = {1748-3190},
mesh = {Animals ; *Flight, Animal/physiology ; *Wings, Animal/physiology ; *Wind ; *Equipment Design ; *Biomimetic Materials/chemistry ; Computer Simulation ; Models, Biological ; Equipment Failure Analysis ; Biomimetics/instrumentation/methods ; Energy Transfer ; Birds/physiology ; Feathers/physiology ; Computer-Aided Design ; },
abstract = {We improve the aerodynamic performance of a simplified vertical-axis wind turbine (VAWT) using a biomimetic flap, inspired by the movement of secondary feathers of a bird's wing at landing (Liebe 1979Aerokurier1254). The VAWT considered has three NACA0018 straight blades at the Reynolds number of80000based on the turbine diameter and free-stream velocity. The biomimetic flap is made of a rigid rectangular curved plate, and its streamwise length is 0.2cand axial (spanwise) length is the same as that of blade, wherecis the blade chord length. This device is installed on the inner surface of each blade. Its one side is attached near the blade leading edge (pivot point), and the other side automatically rotates around the pivot point (without external power input) in response to the surrounding flow field during blade rotation. The flap increases the time-averaged power coefficient by 88% at the tip-speed ratio of 0.8, when its pivot point is at 0.1cdownstream from the blade leading edge. While the torque on the blade itself does not change even in the presence of the flap, the flap itself generates additional torque, thus increasing the overall power coefficient. The phase analysis indicates that the power coefficient of VAWT significantly increases during flap opening to full deployment through the interaction with vortices separated from the blade leading edge. When the pivot point of flap is farther downstream from the leading edge or the flap operates at a high tip-speed ratio, the performance of the flap diminishes due to its weaker interaction with the separating vortices.},
}

Animals
*Flight, Animal/physiology
*Wings, Animal/physiology
*Wind
*Equipment Design
*Biomimetic Materials/chemistry
Computer Simulation
Models, Biological
Equipment Failure Analysis
Biomimetics/instrumentation/methods
Energy Transfer
Birds/physiology
Feathers/physiology
Computer-Aided Design

@article {pmid39621288,
year = {2024},
author = {Palahnuk, H and Su, B and Harbaugh, T and Gesenberg, C and Zhou, S and Rizk, E and Bernstein, J and Hazard, SW and Manning, KB},
title = {Fluid Dynamic and in Vitro Blood Study to Understand Catheter-Related Thrombosis.},
journal = {Cardiovascular engineering and technology},
volume = {},
number = {},
pages = {},
pmid = {39621288},
issn = {1869-4098},
support = {UL1 TR002014/TR/NCATS NIH HHS/United States ; },
abstract = {PURPOSE: Central venous catheters (CVCs) provide a direct route to the venous circulation but are prone to catheter-related thrombosis (CRT). A known CRT risk factor is a high catheter-to-vein ratio (CVR), or a large catheter diameter with respect to the indwelling vein size. In this study, the CVR's effect on CVC hemodynamics and its impact on CRT is investigated with in vitro and in silico experiments.

METHODS: An in vitro flow loop is used to characterize the hemodynamics around CVCs using particle image velocimetry. In addition, CRT is investigated using an in vitro flow loop with human blood and clinical catheters. The wall shear rate of flow around the CVC is computed numerically. CVRs of 0.20, 0.33, and 0.49 and Reynolds numbers of 200, 800, and 1300 are evaluated. No flow is used through CVC lumens to model chronic indwelling catheters.

RESULTS: Results show CVR ≥ 0.33 promotes platelet-rich clot growth at the device tip and at an increased rate compared to lower CVR cases. A high wall shear rate gradient on the CVC tip and an extended wake distal to the tip exists for higher CVR cases, promoting the aggregation of platelets and subsequent stagnation for clot formation. Further, the combination of the CVR and Reynolds number are crucial to CRT potential, not the CVR alone. Specifically, thrombosis risk is increased with low (stasis driven) and/or high (platelet activation driven) flow conditions, with the CVR and CVC's geometry playing an additional role in promoting fluid mechanic driven thrombus development. A high CVR (≥ 0.33) and high flow condition (≥ 1300) results in the highest risk for clot growth at the tip of the device; other locations of the device are at risk for thrombus development in lower flow conditions, regardless of the CVR. The importance of the device geometry and flow in promoting thrombus and fibrin sheath formation is also shown for the device investigated.

CONCLUSIONS: This work demonstrates that the CVR, flow, and device geometry affect CRT. For clinical cases with CVR ≥ 0.33 and/or Re ≥ 1300, the device tip may be monitored more consistently for clot formation. Thrombosis risks remain on the entire catheter, regardless of the flow condition, for a CVR = 0.49. Device placement should be chosen carefully with respect to the combination of the Reynolds number and CVR. Further study is needed on the effect of catheterization to confirm these findings.},
}

@article {pmid39619498,
year = {2024},
author = {Harte, NC and Obrist, D and Versluis, M and Jebbink, EG and Caversaccio, M and Wimmer, W and Lajoinie, G},
title = {Second order and transverse flow visualization through three-dimensional particle image velocimetry in millimetric ducts.},
journal = {Experimental thermal and fluid science},
volume = {159},
number = {},
pages = {None},
pmid = {39619498},
issn = {1879-2286},
abstract = {Despite recent advances in 3D particle image velocimetry (PIV), challenges remain in measuring small-scale 3D flows, in particular flows with large dynamic range. This study presents a scanning 3D-PIV system tailored for oscillatory flows, capable of resolving transverse flows less than a percent of the axial flow amplitude. The system was applied to visualize transverse flows in millimetric straight, toroidal, and twisted ducts. Two PIV analysis techniques, stroboscopic and semi-Lagrangian PIV, enable the quantification of net motion as well as time-resolved axial and transverse velocities. The experimental results closely align with computational fluid dynamics (CFD) simulations performed in a digitized representation of the experimental model. The proposed method allows the examination of periodic flows in systems down to microscopic scale and is particularly well-suited for applications that cannot be scaled up due to their complex, multi-physics nature.},
}

@article {pmid39613755,
year = {2024},
author = {Du, P and Parikh, MH and Fan, X and Liu, XY and Wang, JX},
title = {Conditional neural field latent diffusion model for generating spatiotemporal turbulence.},
journal = {Nature communications},
volume = {15},
number = {1},
pages = {10416},
pmid = {39613755},
issn = {2041-1723},
support = {N00014-23-1-2071//United States Department of Defense | United States Navy | ONR | Office of Naval Research Global (ONR Global)/ ; OAC-2047127//National Science Foundation (NSF)/ ; },
abstract = {Eddy-resolving turbulence simulations are essential for understanding and controlling complex unsteady fluid dynamics, with significant implications for engineering and scientific applications. Traditional numerical methods, such as direct numerical simulations (DNS) and large eddy simulations (LES), provide high accuracy but face severe computational limitations, restricting their use in high-Reynolds number or real-time scenarios. Recent advances in deep learning-based surrogate models offer a promising alternative by providing efficient, data-driven approximations. However, these models often rely on deterministic frameworks, which struggle to capture the chaotic and stochastic nature of turbulence, especially under varying physical conditions and complex, irregular geometries. Here, we introduce the Conditional Neural Field Latent Diffusion (CoNFiLD) model, a generative learning framework for efficient high-fidelity stochastic generation of spatiotemporal turbulent flows in complex, three-dimensional domains. CoNFiLD synergistically integrates conditional neural field encoding with latent diffusion processes, enabling memory-efficient and robust generation of turbulence under diverse conditions. Leveraging Bayesian conditional sampling, CoNFiLD flexibly adapts to various turbulence generation scenarios without retraining. This capability supports applications such as zero-shot full-field flow reconstruction from sparse sensor data, super-resolution generation, and spatiotemporal data restoration. Extensive numerical experiments demonstrate CoNFiLD's capability to accurately generate inhomogeneous, anisotropic turbulent flows within complex domains. These findings underscore CoNFiLD's potential as a versatile, computationally efficient tool for real-time unsteady turbulence simulation, paving the way for advancements in digital twin technology for fluid dynamics. By enabling rapid, adaptive high-fidelity simulations, CoNFiLD can bridge the gap between physical and virtual systems, allowing real-time monitoring, predictive analysis, and optimization of complex fluid processes.},
}

@article {pmid39609494,
year = {2024},
author = {Abderrahmane, A and Younis, O and Ahmed, SE and Mourad, A and Raizha, Z and Ahmed, A},
title = {Magnetic mixed convection within wavy trapezoidal thermal energy storage systems using nano enhanced phase change material.},
journal = {Scientific reports},
volume = {14},
number = {1},
pages = {29565},
pmid = {39609494},
issn = {2045-2322},
support = {RGP2/47/45//the Deanship of Research and Graduate Studies at King Khalid University/ ; },
abstract = {The three-dimensional (3D) MHD mixed convection mode confined 3D wavy trapezoidal enclosure is examined. The bottom plane of the trapezoidal system is irregular, particularly a wavy plane with various undulation numbers [Formula: see text]. The forced convection phenomenon arises due to the displacement of the top region plane, whereas the porosity-enthalpy methodology characterizes the progression of charging. The heat transfer is enhanced using the nanoencapsulation phase change material (NePCM), consisting of Polyurethane as a shell and Nonadecane as a core, with water as the primary liquid base. The (GFEM) is used to treat the governing system, and a comparison between the HT (heat transmission) irreversibility and FF (fluid friction) irreversibility is performed using the function of the BeAvg. The significant findings revealed that parabolic behaviors for the melting ribbon curve are given at lower values of Re and higher values of Ha. Also, reducing the undulation number is better for obtaining a higher heat transmission rate. The average Nusselt number was lowered by 60% and 19%, respectively, at the highest Reynolds number when the Hartmann number increased from 0 to 100 and N from 2 to 8. Also, the values of [Formula: see text] between 1 and 100 improve the heat transfer rates up to 51%.},
}

@article {pmid39597362,
year = {2024},
author = {Sawka, A},
title = {Nanocrystalline Lanthanum Oxide Layers on Tubes Synthesized Using the Metalorganic Chemical Vapor Deposition Technique.},
journal = {Materials (Basel, Switzerland)},
volume = {17},
number = {22},
pages = {},
pmid = {39597362},
issn = {1996-1944},
abstract = {Lanthanum oxide (La2O3) layers are widely used in electronics, optics, and optoelectronics due to their properties. Lanthanum oxide is also used as a dopant, modifying and improving the properties of other materials in the form of layers, as well as having a large volume. In this work, lanthanum oxide layers were obtained using MOCVD (Metalorganic Chemical Vapor Deposition) on the inner walls of tubular substrates at 600-750 °C. The basic reactant was La(tmhd)3 (tris(2,2,6,6-tetramethyl-3,5-heptanedionato)lanthanum(III)). The evaporation temperature of La(tmhd)3 amounted to 170-200 °C. Pure argon (99.9999%) and air were used as the carrier gases. The air was also intended to remove the carbon from the synthesized layers. Tubes of quartz glass were used as the substrates. La2O3 layers were found to be growing on their inner surfaces. The value of the extended Grx/Rex[2] criterion, where Gr-Grashof's number, Re-Reynolds' number, x-the distance from the gas inflow point, was below 0.01. The microstructure of the deposited layers of lanthanum oxide was investigated using an electron scanning microscope (SEM). Their chemical composition was analyzed via energy-dispersive X-ray (EDS) analysis. Their phase composition was tested via X-ray diffraction. The transmittance of the layers of lanthanum oxide was determined with the use of UV-Vis spectroscopy. The obtained layers of lanthanum oxide were characterized by a nanocrystalline microstructure and stable cubic structure. They also exhibited good transparency in both ultraviolet (UV) and visible (Vis) light.},
}

@article {pmid39597124,
year = {2024},
author = {Blaschke, O and Kluitmann, J and Elsner, J and Xie, X and Drese, KS},
title = {Consistent Evaluation Methods for Microfluidic Mixers.},
journal = {Micromachines},
volume = {15},
number = {11},
pages = {},
pmid = {39597124},
issn = {2072-666X},
support = {031B1124A//Federal Ministry of Education and Research/ ; },
abstract = {The study presents a unifying methodology for characterizing micromixers, integrating both experimental and simulation techniques. Focusing on Dean mixer designs, it employs an optical evaluation for experiments and a modified Sobolev norm for simulations, yielding a unified dimensionless characteristic parameter for the whole mixer at a given Reynolds number. The results demonstrate consistent mixing performance trends across both methods for various operation points. This paper also proposes enhancements in the evaluation process to improve accuracy and reduce noise impact. This approach provides a valuable framework for optimizing micromixer designs, essential in advancing microfluidic technologies.},
}

@article {pmid39590232,
year = {2024},
author = {Reynolds, A},
title = {Swarming Insects May Have Finely Tuned Characteristic Reynolds Numbers.},
journal = {Biomimetics (Basel, Switzerland)},
volume = {9},
number = {11},
pages = {},
pmid = {39590232},
issn = {2313-7673},
support = {BBS/OS/CP/000001//Biotechnology and Biological Sciences Research Council's Industrial Strategy Challenge Fund./ ; },
abstract = {Over the last few years, there has been much effort put into the development and validation of stochastic models of the trajectories of swarming insects. These models typically assume that the positions and velocities of swarming insects can be represented by continuous jointly Markovian processes. These models are first-order autoregressive processes. In more sophisticated models, second-order autoregressive processes, the positions, velocities, and accelerations of swarming insects are collectively Markovian. Although it is mathematically conceivable that this hierarchy of stochastic models could be extended to higher orders, here I show that such a procedure would not be well-based biologically because some terms in these models represent processes that have the potential to destabilize insect flight dynamics. This prediction is supported by an analysis of pre-existing data for laboratory swarms of the non-biting midge Chironomus riparius. I suggest that the Reynolds number is a finely tuned property of swarming, as swarms may disintegrate at both sufficiently low and sufficiently high Reynolds numbers.},
}

@article {pmid39562910,
year = {2024},
author = {McMullen, RM and Gallis, MA},
title = {Hydrodynamic fluctuations near a Hopf bifurcation: Stochastic onset of vortex shedding behind a circular cylinder.},
journal = {Physical review. E},
volume = {110},
number = {4-2},
pages = {045104},
doi = {10.1103/PhysRevE.110.045104},
pmid = {39562910},
issn = {2470-0053},
abstract = {We investigate hydrodynamic fluctuations in the flow past a circular cylinder near the critical Reynolds number Re_{c}
for the onset of vortex shedding. Starting from the fluctuating Navier-Stokes equations, we perform a perturbation expansion around Re_{c}
to derive analytical expressions for the statistics of the fluctuating lift force. Molecular-level simulations using the direct simulation Monte Carlo method support the theoretical predictions of the lift power spectrum and amplitude distribution. Notably, we have been able to collect sufficient statistics at distances Re/Re_{c}-
1=O(10^{-3})
from the instability that confirm the appearance of non-Gaussian fluctuations, and we observe that they are associated with intermittent vortex shedding. These results emphasize how unavoidable thermal-noise-induced fluctuations become dramatically amplified in the vicinity of oscillatory flow instabilities and that their onset is fundamentally stochastic.},
}

@article {pmid39562882,
year = {2024},
author = {Śnieżek, D and Naqvi, SB and Matyka, M},
title = {Inertia onset in disordered porous media flow.},
journal = {Physical review. E},
volume = {110},
number = {4-2},
pages = {045103},
doi = {10.1103/PhysRevE.110.045103},
pmid = {39562882},
issn = {2470-0053},
abstract = {We investigate the onset of the inertial regime in the fluid flow at the pore level in three-dimensional, disordered, highly porous media. We analyze the flow structure in a wide range of Reynolds numbers starting from 0.01 up to 100. We focus on qualitative and quantitative changes that appear with increasing Reynolds number. To do that, we investigate the weakening of the channeling effect, defined as the existence of preferred flow paths in a system. We compute tortuosity, spatial kinetic energy localization, and the pore-space volume fraction containing negative streamwise velocity to assess accompanying changes quantitatively. Our results of tortuosity and participation number derivatives show that the onset of inertia is apparent for Reynolds number Re∼0.1, an order of magnitude lower than indicated by analyzing relations of friction factor with the Reynolds number. Moreover, we show that the vortex structures appear at Reynolds number two orders of magnitude higher than the onset of inertia.},
}

@article {pmid39561136,
year = {2024},
author = {Depoilly, F and Millet, S and Ben Hadid, H and Dagois-Bohy, S and Rousset, F},
title = {Unifying the roll waves.},
journal = {PloS one},
volume = {19},
number = {11},
pages = {e0310805},
pmid = {39561136},
issn = {1932-6203},
mesh = {*Rheology ; Viscosity ; *Models, Theoretical ; },
abstract = {Free surface flows down a slope occur in various real-life scenarios, such as civil engineering, industry, and natural hazards. Unstable waves can develop at the free surface when inertia is sufficiently strong, indicated by the Reynolds number exceeding a critical value. Although this instability has been investigated for specific fluids with different rheologies, a common framework is still lacking to facilitate comparison among the various models. In this study, we investigate the linear stability of a generalized Newtonian fluid, where the viscosity [Formula: see text] remains unspecified. We meticulously construct new dimensionless quantities to minimize dependence on the rheology, and subsequently derive the Orr-Sommerfeld equation of stability for any generalized Newtonian fluid, which has never been done before. We conduct a long-wave expansion and generate a novel analytical expression for the wave celerity, along with the critical Reynolds number. The originality in this study is that the analytical expressions obtained are valid for any rheology, and are easy to compute from a rheological measurement or from a base flow profile measurement. These results are subsequently scrutinized using various shear-thinning, shear-thickening, and viscoplastic rheology models. They exhibit excellent agreement with experimental or numerical data as well as theoretical findings from existing literature. Furthermore, the novel analytical expressions enable a much more comprehensive investigation into the impact of rheology on stability. While our approach does not encompass singular or non-monotonous rheology, the analytical expressions derived from the long-wave expansion exhibit remarkable resilience and they continue to accurately predict both the wave speed and the instability threshold in such cases.},
}

*Rheology
Viscosity
*Models, Theoretical

@article {pmid39553381,
year = {2024},
author = {Kadivar, M and Tormey, D and McGranaghan, G},
title = {CFD of roughness effects on laminar heat transfer applied to additive manufactured minichannels.},
journal = {Heat and mass transfer = Warme- und Stoffubertragung},
volume = {60},
number = {12},
pages = {1915-1929},
pmid = {39553381},
issn = {0947-7411},
abstract = {Additive manufacturing has received significant interest in the fabrication of functional channels for heat transfer; however, the inherent rough surface finish of the additively manufactured channels can influence thermal performance. This study investigates the impact of roughness on the thermo-fluid characteristics of laminar forced convection in rough minichannels. A numerical model was developed to create 3D Gaussian roughness with specified root-mean-square height. The finite volume method was used to solve the conjugate heat transfer of developed laminar flow in square minichannels. For Reynolds numbers ranging from 200 to 1600, the simulation results indicated enhanced heat transfer and increased flow resistance as Reynolds number increases, compared to a smooth minichannel, where effects on heat transfer and flow friction were negligible. For channels with relative roughness (root-mean-square height to channel hydraulic diameter) of 0.0068, 0.0113, and 0.0167, increasing the Reynolds number led to increased friction factor by 1.56, 1.71, and 2.91%, while the Nusselt number was enhanced up to 0.03%, 32.74%, and 46.05%, respectively. Heat transfer reduced in roughness valleys due to the presence of local low-velocity fluid in these regions; however, recirculation regions can occur in deep valleys of high roughness, increasing heat transfer and flow friction. Heat transfer was enhanced over roughness peaks due to flow impingement on the windward face of roughness as well as intensified energy transfer to the channel wall from roughness. Moreover, surfaces with higher roughness have a greater number of high peaks providing a thermal-flow path of a larger area and a thermal conductivity greater than that of the fluid.},
}

@article {pmid39551763,
year = {2024},
author = {Yi, S and Ding, H and Luo, S and Sun, X and Xia, Z},
title = {Research progress on aero-optical effects of hypersonic optical window with film cooling.},
journal = {Light, science & applications},
volume = {13},
number = {1},
pages = {310},
pmid = {39551763},
issn = {2047-7538},
support = {12102463//National Natural Science Foundation of China (National Science Foundation of China)/ ; 92271203//National Natural Science Foundation of China (National Science Foundation of China)/ ; },
abstract = {In recent years, the demand for optical imaging and detection in hypersonic aircraft has been on the rise. The high-temperature and high-pressure compressed flow field near airborne optoelectronic devices creates significant interference with light transmission, known as hypersonic aero-optical effects. This effect has emerged as a key technological challenge, limiting hypersonic optical imaging and detection capabilities. This article focuses on introducing the thermal effects and optical transmission effects of hypersonic aero-optical effects, as along with corresponding suppression techniques. In addition, this article critically reviews and succinctly summarizes the advancements made in hypersonic aero-optical effects testing technology, while also delineating avenues for future research needs in this field. In conclusion, there is an urgent call for further exploration into the study of aero-optical effects under conditions characterized by high Mach, high enthalpy, and high Reynolds number in the future.},
}

@article {pmid39524866,
year = {2024},
author = {Monokrousos, N and Könözsy, L and Pachidis, V and Sozio, E and Rossi, F},
title = {A numerical approach to overcome the very-low Reynolds number limitation of the artificial compressibility for incompressible flows.},
journal = {Heliyon},
volume = {10},
number = {21},
pages = {e39587},
pmid = {39524866},
issn = {2405-8440},
abstract = {We propose a numerical approach to solve a long-standing challenge which is the applicability of the artificial compressibility (AC) formulation for solving the incompressible Navier-Stokes equations at very-low Reynolds numbers. A wide range of engineering applications involves very-low Reynolds number flows in Micro-ElectroMechanical Systems (MEMS) and in the fields of chemical-, agricultural- and biomedical engineering. It is known that the already existing numerical methods using the AC approach fail to provide physically correct results at very-low Reynolds numbers (Re ≤ 1). To overcome the limitation of the AC method for these engineering applications, we propose a higher-order Neumann-type pressure outflow boundary condition treatment along with their up to fourth-order numerical approximations. We found that the numerical treatment of the pressure at the outlet boundary plays the main role in overcoming the limitation of the AC method at very-low Reynolds numbers (Re << 1). Therefore, we provide numerical evidence on the accuracy of the AC method beyond its previously reported limitations, e.g., the low Reynolds number Oseen flow (Re << 1) is first presented in this work. A third-order explicit total-variation diminishing (TVD) Runge-Kutta scheme has been employed with standard finite difference spatial discretisation schemes for improving the accuracy of the numerical solution. For modelling strongly viscous flows, the Reynolds number ranges from 10 - 1 to 10 - 4 . Overall, we found that the accuracy limitation of the AC method below Re < 1 can be overcome with an accurate numerical treatment of the outlet pressure boundary condition instead of using high-order schemes in the governing equations. For the investigated Reynolds number range (10 - 1 ≤ Re ≤ 10 - 4), the obtained results show that the relative errors were smaller than 1% for the numerical simulations performed on the configurations of both the two- and three-dimensional, straight microfluidic channels. The imposition of high-order derivative Neumann-type pressure outflow boundary conditions reduced the maximum relative errors of the numerical solutions from 85% and 95% to below than 1% at the outlet section of the two- and three-dimensional, straight microfluidic channel flows, respectively. Taking the advantage of the numerical approach proposed here, two- and three-dimensional benchmark problems employed in the current investigation in comparison with analytical solutions available in the literature, clearly demonstrate that the artificial compressibility can be used beyond its previously known constraints for very-low Reynolds number incompressible flows.},
}

@article {pmid39532903,
year = {2024},
author = {Vishwakarma, DK and Bhattacharyya, S and Soni, MK},
title = {Thermal and flow dynamics of an inclined air heat exchanger equipped with spring turbulators in the transition flow regime.},
journal = {Scientific reports},
volume = {14},
number = {1},
pages = {27640},
pmid = {39532903},
issn = {2045-2322},
abstract = {The research involves an experimental investigation into the performance of a flow assisting air heat exchanger under varying angular orientation and uniform external heat fluxes without and with spring turbulators. The investigation was performed for Reynolds numbers ranging from 511 to 9676 and inclination angle 15° and 30°. Three heat fluxes (2, 3, and 4 kW/m[2]) were applied to the test section to investigate the effect of external surface heating on the range of transition flow regime and thermohydraulic performance. Transition from laminar to turbulent flow for plain channel at different heat fluxes and inclinations occurs within specific Reynolds number ranges: 2436-4446 for 15° inclination at 4 kW/m[2], 2574-4289 at 3 kW/m[2], and 2850-4152 at 2 kW/m[2]; for 30° inclination, the ranges are 2518-4151, 2712-4361, and 2992-4346 at the respective heat fluxes. When it comes to the effect of inclination on Nusselt number, the transition occurs sooner at lower angles, but is delayed as the angle increases. Additionally, the Nusselt number decreases as the angle of inclination increases. When comparing the Nusselt numbers of plain tubes to those with spring turbulators, the latter shows a significantly greater enhancement. In laminar flow, a maximum 100% deviation exists between highest and lowest friction factors, decreasing to 75% with increasing Reynolds number; all insert configurations exhibit highest friction factor at 15° due to stronger buoyancy forces.},
}

@article {pmid39530646,
year = {2024},
author = {Thouvenot, E and Charnay, L and Burshtein, N and Guigner, JM and Dec, L and Loew, D and Silva, AKA and Lindner, A and Wilhelm, C},
title = {High-Yield Bioproduction of Extracellular Vesicles from Stem Cell Spheroids via Millifluidic Vortex Transport.},
journal = {Advanced materials (Deerfield Beach, Fla.)},
volume = {},
number = {},
pages = {e2412498},
doi = {10.1002/adma.202412498},
pmid = {39530646},
issn = {1521-4095},
support = {682367//ERC Consolidator Grant PaDyFlow/ ; N°EX061034//la Région Île-de-France/ ; //ITMO Cancer of Aviesan/ ; 21CQ016-00//Inserm/ ; ERC-2019-CoG project NanoBioMade 865629//HORIZON EUROPE European Research Council/ ; },
abstract = {Extracellular vesicles (EVs) are emerging as novel therapeutics, particularly in cancer and degenerative diseases. Nevertheless, from both market and clinical viewpoints, high-yield production methods using minimal cell materials are still needed. Herein, a millifluidic cross-slot chip is proposed to induce high-yield release of biologically active EVs from less than three million cells. Depending on the flow rate, a single vortex forms in the outlet channels, exposing transported cellular material to high viscous stresses. Importantly, the chip accommodates producer cells within their physiological environment, such as human mesenchymal stem cells (hMSCs) spheroids, while facilitating their visualization and individual tracking within the vortex. This precise control of viscous stresses at the spheroid level allows for the release of up to 30000 EVs per cell at a Reynolds number of ≈400, without compromising cellular integrity. Additionally, it reveals a threshold initiating EV production, providing evidence for a stress-dependent mechanism governing vesicle secretion. EVs mass-produced at high Reynolds displayed pro-angiogenic and wound healing capabilities, as confirmed by proteomic and cytometric analysis of their cargo. These distinct molecular signatures of these EVs, compared to those derived from monolayers, underscore the critical roles of the production method and the 3D cellular environment in EV generation.},
}

@article {pmid39528766,
year = {2024},
author = {Hassaan, AM},
title = {An experimental investigation examining the usage of a hybrid nanofluid in an automobile radiator.},
journal = {Scientific reports},
volume = {14},
number = {1},
pages = {27597},
pmid = {39528766},
issn = {2045-2322},
abstract = {Several modifications have been made to the radiator's dimensions and materials as part of the evolution of the automotive cooling cycle. Coolant is an important factor that greatly affects the efficiency of the cooling cycle. In applications involving heat transmission, nanofluids have become a viable possibility coolant. Two distinct types of nanoparticles floating in the base fluid make up the hybrid nanofluid, a newly invented class of nanofluids. Tests of hybrid nanofluids as a working fluid substitute for conventional fluids have been assisted by the current study. In the radiator of a 2005 Honda, the MWCNT-Al2O3/water nanofluid was tested at various volumetric concentrations (Φ) using a 50:50 mixing ratio. The outcomes of the experiments were compared with those obtained by using pure water. The radiator's performance was evaluated by adjusting the fluid flow rate and operating the fluid at two distinct temperatures (60, 80 °C). The outcomes demonstrated that the convection heat transfer coefficient increased with a ratio reached 28.5% over the distilled water at the same temperature and flow rate. Both effectiveness and the Nusselt number had improved, coming in at 22.54% and 23.74%, respectively. Depending on the fluid concentration there is an increase in the pressure drop up to 24% than ordinary fluid. It discovered considerable agreement between the research outcomes by comparing them with earlier publications. An experimental correlation was inferred from the results to estimate the Nusselt number as a function of the Reynolds number and (Φ).},
}

@article {pmid39520057,
year = {2025},
author = {Noreen, S and Aslam, F},
title = {Electro-Osmotic Mechanism of Ellis Fluid With Joule Heating, Viscous Dissipation, and Magnetic Field Effects in a Pumping Microtube.},
journal = {Journal of biomechanical engineering},
volume = {147},
number = {1},
pages = {},
doi = {10.1115/1.4067083},
pmid = {39520057},
issn = {1528-8951},
mesh = {Viscosity ; *Magnetic Fields ; Hot Temperature ; Osmosis ; Hydrodynamics ; Rheology ; },
abstract = {The dynamics of electro-osmotically generated flow of biological viscoelastic fluid in a cylindrical geometry are investigated in this paper. This flux is the result of walls contracting and relaxing sinusoidally in a magnetic environment. The blood's viscoelasticity and shear-thinning viscosity are the primary causes of its non-Newtonian characteristics. Hence, the rheology of the fluid (blood) is accurately captured with the Ellis fluid model. Both Joule heating and viscous dissipation are accounted for during thermal analysis. The electric potential induced in the electric double layer (EDL) is obtained by applying the Debye-Huckel linearization to the nonlinear Poisson-Boltzmann equation. Mathematical modelling is incorporated in cylindrical coordinates in wave frame of reference. Assuming a long wavelength and creeping flow characterized by a low Reynolds number, the Ellis fluid model's governing equations are simplified. The resulting differential equations are evaluated numerically via the built-in tool NDSolve of the Mathematica. Graphical representations are utilized to visually and comprehensively assess the thermal characteristics, flow features, heat transfer coefficient, and skin friction coefficient. Various factors are taken into consideration, including the impact of Ellis fluid parameters, electric double layer, magnetic field, Brinkman number, and Ohmic dissipation. Ellis fluid's axial velocity boosts with a rise of the electro-osmotic parameter and power-law index while decreasing with an increase in the Hartmann number and material fluid parameter. The fluid temperature is directly proportional to EDL parameter and parameters of Ohmic and viscous dissipation. The presence of both electric and magnetic fields may aid in the management and control of Ellis fluid (blood) mobility at different temperatures, which is helpful in controlling bleeding during surgeries. The current model may be used in clinical scenarios involving the gastrointestinal system and capillaries, electrohydrodynamic therapy, delivery of drugs in pharmacological, and biomedical devices. This research creates a theoretical model that can predict the effects of different parameters on the characteristics of fluid flows that are like blood.},
}

Viscosity
*Magnetic Fields
Hot Temperature
Osmosis
Hydrodynamics
Rheology

@article {pmid39512462,
year = {2024},
author = {Kananipour, M and Mohseni, MM and Jahanmardi, R and Khonakdar, HA},
title = {Heat and mass transfer analysis of s-PTT nanofluid in microchannels under combined electroosmotic and pressure-driven flows with wall slip using the homotopy perturbation method.},
journal = {Heliyon},
volume = {10},
number = {21},
pages = {e39526},
pmid = {39512462},
issn = {2405-8440},
abstract = {The heat and mass transfer of the electroosmotic flow in microchannel transporting viscoelastic nanofluid is investigated considering Brownian motion of nanoparticles and slip boundary conditions. The simplified Phan-Thien-Tanner model is employed to describe the rheological behavior of fluid and the nonlinear Navier model with non-zero slip critical shear stress is considered at walls. The governing nonlinear momentum, mass, and heat transfer equations are solved using the Homotopy Perturbation Method. The study reveals that increasing the fluid elasticity, nanoparticle concentration, and size significantly enhances the flow rate, heat and mass transfer. Additionally, elasticity and Reynolds number decrease the friction factor. Reducing the double-layer thickness and increasing the Reynolds number lead to higher flow rates and fluid velocities. Notably, the findings emphasize the critical role of the slip conditions on the Sherwood and Nusselt numbers.},
}

@article {pmid39507597,
year = {2024},
author = {Karyawan, and Suwasono, B and Supartono, and Syamsuar, S and Muharam, A and Widyawasta, and Pane, IZ and Haryanto, I and Tauviqirrahman, M and Yohana, E},
title = {Dataset of the twin floater of amphibian aircraft in wind tunnel test.},
journal = {Data in brief},
volume = {57},
number = {},
pages = {111008},
pmid = {39507597},
issn = {2352-3409},
abstract = {It is well known that seaplanes have twin floaters. Therefore, it is necessary to conduct a wind tunnel test that aims to determine the performance of twin floaters paired on a mock aircraft model. The twin floaters use the same scale as the mock aircraft, which is 1:6.3 with a length of 1555 mm and a distance between floaters of 668.8 mm or S/L of 0.43. The test plan uses a speed of 65 m s[-1] and a Reynolds number 1.5 times the model configuration with flap angle variations of 0°, 10°, 18°, 30°, and 40°. The final test results showed that tabulations and graphs of lift coefficient (CL), drag coefficient (CD), and pitching moment coefficient (CM) with angle of attack (α) variations of -10° to 16°.},
}

@article {pmid39501069,
year = {2024},
author = {Venkateswaran, VK and Fernandez-Gamiz, U and Portal-Porras, K and Blanco, JM},
title = {Numerical study on aerodynamics of small scale horizontal axis wind turbine with Weibull analysis.},
journal = {Scientific reports},
volume = {14},
number = {1},
pages = {26790},
pmid = {39501069},
issn = {2045-2322},
support = {Energ´ıa eo´lica offshore 348 para el ensayo y el desarrollo energe´tico de energ´ıas renovables e hidro´geno verde//Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas/ ; Energ´ıa eo´lica offshore 348 para el ensayo y el desarrollo energe´tico de energ´ıas renovables e hidro´geno verde//Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas/ ; IT1514-22//Ekonomiaren Garapen eta Lehiakortasun Saila, Eusko Jaurlaritza/ ; IT1514-22//Ekonomiaren Garapen eta Lehiakortasun Saila, Eusko Jaurlaritza/ ; },
abstract = {This paper presents a computational fluid dynamics (CFD) analysis and blade element momentum (BEM) analysis of horizontal small-scale wind turbines under various parameters. Random airfoils such as the NACA 0012, NACA 0018, NACA 4412, S1016, S1210, S1223, and SC20402 are chosen, and the glide ratio is analysed. A Reynolds number of 100,000 is considered because of the small wind turbine design. The foil with the highest glide ratio is selected. Various notations are used to represent the chord and the twist angle of the blade, and the blade with the best chord and twist angle is chosen. The lift, drag, and power coefficients and power curves are analysed via the BEM. The power curves are evaluated for different air densities, and a higher value of power is obtained. Finally, via CFD, the SST K - ω model for turbulence is analysed for various angles of attack via Ansys Fluent for different air densities. The results are satisfactory compared with those of the CFD and BEM analyses. The Weibull distribution is analysed to understand the required frequencies for various wind speeds so that the installation of wind turbines can be made convenient in preferred areas with suitable wind properties.},
}

@article {pmid39467183,
year = {2024},
author = {Roy, A and Dhar, P},
title = {Capillary Orientation and Morphology Dictated Oscillatory Electro-magneto-imbibition of Viscoelastic Electrolytes.},
journal = {Langmuir : the ACS journal of surfaces and colloids},
volume = {40},
number = {45},
pages = {23788-23805},
doi = {10.1021/acs.langmuir.4c02762},
pmid = {39467183},
issn = {1520-5827},
abstract = {We explore the intricate dynamics of imbibition by a viscoelastic electrolyte within an arbitrarily oriented, nonuniform microcapillary, while under the stimulus of external electromagnetic fields and internal electroviscous forces stemming from streaming potential. The microcapillary walls are envisaged to be tapered relative to each other, with the entire system inclined with respect to the horizontal plane. The rheological behavior of the electrolyte is characterized using the Phan-Thien-Tanner (PTT) model. To manipulate the imbibition dynamics, external transverse magnetic and electric fields are imposed. Incorporating all contributing forces, we obtain semianalytical formulations for the velocity and shear stress distributions. We identify distinct stages during the imbibition process: (i) initial, (ii) filling, (iii) oscillatory, and (iv) stagnation stages. Moreover, we scrutinize the impact of four pivotal parameters, namely, the Weissenberg number (Wi), the Hartmann number (Ha), the transverse electric to viscous force (EVF) number (S), and the electric Reynolds number (Ree), on the imbibition dynamics across different inclinations and taper angles. We also delineate the parameter space for these four parameters, identifying where the onset of oscillations occurs. Finally, through scaling analysis, we establish the existence of four distinct regimes corresponding to the aforementioned stages: (i) the linear regime, (ii) the Washburn regime, (iii) the oscillatory regime, and (iv) the equilibrium regime. Our findings are anticipated to enhance the understanding of capillary imbibition under such complex flow conditions and contribute significantly to the advancement of capillarity-driven microfluidic devices.},
}

@article {pmid39451841,
year = {2024},
author = {Feraru, MD and Măriuța, D and Stoia-Djeska, M and Grigorie, LT},
title = {Numerical Investigation of an NACA 13112 Morphing Airfoil.},
journal = {Biomimetics (Basel, Switzerland)},
volume = {9},
number = {10},
pages = {},
pmid = {39451841},
issn = {2313-7673},
abstract = {This article presents a numerical study on the 2D aerodynamic characteristics of an airfoil with a morphed camber. The operational regime of the main rotor blade of the IAR 330 PUMA helicopter was encompassed in CFD simulations, performed over an angle of attack range of α=[-3°; 18°], and a Mach number of M=0.38. Various degrees of camber adjustment were smoothly implemented to the trailing-edge section of the NACA13112 airfoil, with a corresponding chord length of c=600 mm at the Reynolds number, Re=5.138×106, and the resulting changes in static lift and drag were calculated. The study examines the critical parameters that affect the configuration of the morphing airfoil, particularly the length of the trailing edge morphing. This analysis demonstrates that increasing the morphed camber near the trailing edge enhances lift capability and indicates that the maximum lift of the airfoil depends on the morphed chord length. The suggested approach demonstrates potential and can be implemented across various categories of aerodynamic structures, such as propeller blade sections, tails, or wings.},
}

@article {pmid39442395,
year = {2024},
author = {Moulia, V and Heran, M and Lesage, G and Hamelin, J and Pinta, J and Gazon, A and Penlae, M and Bru-Adan, V and Wéry, N and Ait-Mouheb, N},
title = {Biofilm growth dynamics in a micro-irrigation with reclaimed wastewater in the field scale.},
journal = {Journal of environmental management},
volume = {370},
number = {},
pages = {122976},
doi = {10.1016/j.jenvman.2024.122976},
pmid = {39442395},
issn = {1095-8630},
mesh = {*Biofilms ; *Wastewater ; Biofouling ; Agricultural Irrigation ; Waste Disposal, Fluid/methods ; },
abstract = {The dripper clogging due to the development of biofilm can reduce the benefits of micro-irrigation technology implementation using reclaimed wastewater. The narrow cross-section and labyrinth geometry of the dripper channel enhance the fouling mechanisms. The aim of this study was to evaluate the water distribution and biofouling of drip irrigation systems at the field scale during irrigation with treated wastewater. Six 100 m lines of commercial pipes with two pressure-compensating dripper types (flow rate, Q, of 0.65 L h[-1] and 1.5 L h[-1], respectively) were monitored for four months. Different zones along the pipes were selected to evaluate the influence of hydrodynamical conditions (Reynolds number = 5400 to 0) on biofouling. Destructive methods involving the biofilm extraction by mechanical means, showed little biofilm development without significant differences in dry and organic matter content in function of the sampling location along the pipe or dripper flow rate (Q0.65 and Q1.5). These results were confirmed by non-destructive methods, such as optical coherence tomography, that nevertheless showed that biofouling concerned 15-20% of the total dripper labyrinth volume. Total organic carbon monitoring and its composition (by three-dimensional excitation and emission matrix fluorescence microscopy) showed that the biofilm did not significantly influence the organic matter nature. Our results indicated that the biological activity and biofilm development in irrigation systems were more affected by the environmental conditions, particularly water temperature, rather than flow conditions. This confirmed that treated wastewater with low organic content can be used in micro-irrigation systems without significant loss of efficiency, even in conditions requiring intensive irrigation, such as the Mediterranean climate.},
}

*Biofilms
*Wastewater
Biofouling
Agricultural Irrigation
Waste Disposal, Fluid/methods