Journal articles: 'Menter Shear stress transport'

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Philipbar, Brad M., Jiajia Waters, and David B. Carrington. "A finite element Menter Shear Stress turbulence transport model." Numerical Heat Transfer, Part A: Applications 77, no. 12 (April 20, 2020): 981–97. http://dx.doi.org/10.1080/10407782.2020.1746155.

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Huang, Junji, Jorge-Valentino Bretzke, and Lian Duan. "Assessment of Turbulence Models in a Hypersonic Cold-Wall Turbulent Boundary Layer." Fluids 4, no. 1 (February 26, 2019): 37. http://dx.doi.org/10.3390/fluids4010037.

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In this study, the ability of standard one- or two-equation turbulence models to predict mean and turbulence profiles, the Reynolds stress, and the turbulent heat flux in hypersonic cold-wall boundary-layer applications is investigated. The turbulence models under investigation include the one-equation model of Spalart–Allmaras, the baseline k - ω model by Menter, as well as the shear-stress transport k - ω model by Menter. Reynolds-Averaged Navier-Stokes (RANS) simulations with the different turbulence models are conducted for a flat-plate, zero-pressure-gradient turbulent boundary layer with a nominal free-stream Mach number of 8 and wall-to-recovery temperature ratio of 0.48 , and the RANS results are compared with those of direct numerical simulations (DNS) under similar conditions. The study shows that the selected eddy-viscosity turbulence models, in combination with a constant Prandtl number model for turbulent heat flux, give good predictions of the skin friction, wall heat flux, and boundary-layer mean profiles. The Boussinesq assumption leads to essentially correct predictions of the Reynolds shear stress, but gives wrong predictions of the Reynolds normal stresses. The constant Prandtl number model gives an adequate prediction of the normal turbulent heat flux, while it fails to predict transverse turbulent heat fluxes. The discrepancy in model predictions among the three eddy-viscosity models under investigation is small.

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Zheng, Qiu Ya, and San Yang Liu. "Drag Prediction on DLR-F6 Wing-Body Configuration." Applied Mechanics and Materials 110-116 (October 2011): 1506–11. http://dx.doi.org/10.4028/www.scientific.net/amm.110-116.1506.

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This paper mainly investigate the accuracy of the computed drag on the DLR-F6 Wing-Body configuration, and analyze effect of grid and the turbulence models including the Spalart-Allmaras model, Wilcox’s k-ω model and Menter shear-stress transport model on aerodynamic forces for wing-body configuration. The computed results show that grid refinement has little effect on the pressure distributions, significant effect on drag. The turbulence models have certain effects on the pressure distributions, especially positions of the shock wave. They have obvious effects on drag, particularly friction drag. This study shows that performing the CFD calculation at the same angle-of-attack as experiment resulted in good comparisons with wing surface pressures.

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Sun, M. B., J. H. Liang, and Z. G. Wang. "A modified blending function for zonal hybrid Reynolds-averaged Navier—Stokes/large-eddy simulation methodology." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 223, no. 8 (August 1, 2009): 1067–81. http://dx.doi.org/10.1243/09544100jaero575.

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A modified blending function for zonal hybrid Reynolds averaged Navier—Stokes/large eddy simulation (RANS/LES) methodology was developed using an empirical analogy from Menter k—ω shear stress transport (SST) turbulent model (Menter, 1994) to predict complex turbulent flows. Tests of slot jet in supersonic flow and supersonic flow over compression—expansion ramp was conducted and prediction of separations was well improved when certain model constant was forced on the traditional blending function (Baurle et al., 2003). Analysis based on calculations of flat plate boundary layer demonstrated that an efficient empirical constant could be used in blending function and boundary layer could be well calculated without heavy contamination of RANS on wake region. Validation of the modified zonal hybrid RANS/LES approach for slot jet in supersonic flow, supersonic flow over compression—expansion ramp, supersonic flow over backward facing step, and supersonic cavity flow was conducted. The simulated results showed that the modified blending function performs well on complex turbulent flows. Deficiencies of traditional hybrid zonal RANS/LES method in over-prediction of separations associated with adverse pressure gradient flows were favourably improved.

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Araya, Guillermo. "Turbulence Model Assessment in Compressible Flows around Complex Geometries with Unstructured Grids." Fluids 4, no. 2 (April 28, 2019): 81. http://dx.doi.org/10.3390/fluids4020081.

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One of the key factors in simulating realistic wall-bounded flows at high Reynolds numbers is the selection of an appropriate turbulence model for the steady Reynolds Averaged Navier–Stokes equations (RANS) equations. In this investigation, the performance of several turbulence models was explored for the simulation of steady, compressible, turbulent flow on complex geometries (concave and convex surface curvatures) and unstructured grids. The turbulence models considered were the Spalart–Allmaras model, the Wilcox k- ω model and the Menter shear stress transport (SST) model. The FLITE3D flow solver was employed, which utilizes a stabilized finite volume method with discontinuity capturing. A numerical benchmarking of the different models was performed for classical Computational Fluid Dynamic (CFD) cases, such as supersonic flow over an isothermal flat plate, transonic flow over the RAE2822 airfoil, the ONERA M6 wing and a generic F15 aircraft configuration. Validation was performed by means of available experimental data from the literature as well as high spatial/temporal resolution Direct Numerical Simulation (DNS). For attached or mildly separated flows, the performance of all turbulence models was consistent. However, the contrary was observed in separated flows with recirculation zones. Particularly, the Menter SST model showed the best compromise between accurately describing the physics of the flow and numerical stability.

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Islam, Saad, and Md Shafiqul Islam. "Numerical Analysis for Determination of Hydrodynamic Characteristics of a Gimbaled Thrust Vectoring Nozzle." Journal of Bangladesh Academy of Sciences 41, no. 1 (August 23, 2017): 69–84. http://dx.doi.org/10.3329/jbas.v41i1.33505.

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Gimbaled thrust vectoring nozzles are employed in Solid Rocket Motors (SRM) to account for the aspects of maneuverability of the flight vehicle. The flow field of such a solid pulsed rocket motor is explored numerically (from dome-closeout onward) by solving Reynolds-averaged Navier-Stokes equations with Menters Shear Stress Transport (SST) k - ? turbulence model using a Computational Fluid Dynamics (CFD) tool. Parametric studies are carried out to find out the thermochemical and hydrodynamic characteristics of the hot gas in the rocket motor nozzle. The performances of different supersonic and subsonic sections were studied in terms of the hydrodynamic aspects such as static pressure and Mach number distribution. It is observed that the tradeoff of implementing thrust vectoring mechanism amounts to an additional pressure loss of 10.06% in the rocket motor. Such analyses are specific to certain types of Short Range Ballistic Missiles (SRBM) having solid state propellant (primary stage) in radial boost, end burning pulsed configuration with exacting demands on maneuverability and control implied upon payload and mission criterion.Journal of Bangladesh Academy of Sciences, Vol. 41, No. 1, 69-84, 2017

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Lobanov, I. E. "MATHEMATICAL LOW-REYNOLDS MODELING OF HEAT EXCHANGE IIN TURBULENT FLOW IN FLAT CHANNELS WITH TURBULATORS SYMMETRICALLY LOCATED ON BOTH SIDES." Herald of Dagestan State Technical University. Technical Sciences 45, no. 2 (December 17, 2018): 70–93. http://dx.doi.org/10.21822/2073-6185-2018-45-2-70-93.

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ObjectivesThe aim of the study was to simulate the heat transfer in flat channel with turbulators, symmetrically located on its both sides, depending on the channel's geometric parameters and the coolant flow modes followed by the verification of the obtained calculated data by the existing experiment.MethodsThe calculation was carried out on the basis of a theoretical method based on the solution of the Reynolds equations, closed with the help of the Menter shear stress transport model, by factored finite-volume method, as well as the energy equation on multiscale intersecting structured grids (Fast COmposite Mesh method, FCOM).ResultsA theoretical mathematical calculation model for intensified heat exchange in turbulent flow for a flat channel with turbulators, symmetrically located on both sides, depending on the channel's geometric parameters and coolant flow modes was generated. The calculation results of the intensified heat exchange in flat channels with double turbulators, depending on the determining parameters, are in very good agreement with the existing experimental material and have an undeniable advantage over the latter, since the assumptions made in their derivation cover a much wider range of determining parameters than the limitations of the experiments (Pr = 0.7 ч 100; Re = 103ч 106; h / dЭ= 0.005 ч 0.2; t / h= 1 ч 200). ConclusionAccording to the calculation results based on the developed model, it is possible to optimise the heat exchange intensification in flat channels with double turbulators, as well as to control the process of heat exchange intensification. The comparative calculations of the intensified hydraulic resistance and heat exchange for flat channels with two-sided symmetrical flow turbulators with corresponding data for round channels with turbulators were carried out and analysed. From the point of view of heat exchange intensification, all other conditions being equal, the reduction of a flat channel with two-sided symmetrical turbulators with respect to a round tube with turbulators takes place because a smaller increase in heat exchange is achieved with a greater increase in hydraulic resistance. It was established by calculation that the relative hydraulic resistance ξП/ ξT for channels with turbulators is always higher than for smooth channels; however, the relative heat exchange NuП/ NuT for channels with turbulators can be higher than for smooth channels. Therefore, there is an enhanced redistribution of the temperature drop over the channel section with an intensified heat exchanger. The developed theoretical method based on the solution of the Reynolds equations by the factored finite-volume method, combined with the energy equation on multiscale intersecting structured grids and closed by means of the Menter shear stress transport model, makes it possible, with reasonable accuracy, to calculate heat exchange coefficients and hydraulic resistance in flat channels of practically any forms of double symmetrically located flow turbulators.

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Bekhit, Adham, and Florin Popescu. "URANSE-Based Numerical Prediction for the Free Roll Decay of the DTMB Ship Model." Journal of Marine Science and Engineering 9, no. 5 (April 21, 2021): 452. http://dx.doi.org/10.3390/jmse9050452.

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In the present study, Computational Fluid Dynamics (CFD) is used to investigate the roll decay of the benchmark surface combatant DTMB-5512 ship model appended with bilge keels, sailing in calm water at different speeds (Fr = 0.0, 0.138, 0.2, 0.28 and 0.41) and with different initial roll angles. The numerical simulations are carried out using the viscous flow solver ISIS-CFD of the FINETM/Marine software provided by NUMECA. The solver uses the finite volume method to build the spatial discretization of the transport equation to solve the unsteady Reynolds-Averaged Navier–Stokes equations. Two-phase flow approach is applied to model the air–water interface, where the free surface is captured using the volume of fluid method. The closure to turbulence is achieved by making use of the blended Menter shear stress transport and the explicit algebraic Reynolds stress models. First, a systematic validation against the experimental data at medium speed and initial roll angle of 10° are performed; then, the effect of the initial roll angle and ship speed is later studied. Numerical errors and uncertainties are assessed using grid and time step convergence study based on Richardson Extrapolation method. A special focus on the flow in the vicinity of the bilge keels during the simulation is also investigated and presented in the form of velocity contours and vortical structure formations. The resemblance between the CFD results and experimental data for roll motion and flow characteristics are within a satisfactory congruence; however, some discrepancies are recorded for the over predicted roll amplitudes in the second and, sometimes, the third roll cycle, which appeared mostly in the cases with high initial roll angles.

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Matvienko, O. V., V. A. Arkhipov, and N. N. Zolotorev. "AERODYNAMICS OF A TURBULENT FLOW IN A ROTATING SEMI-CLOSED CYLINDER." Vestnik Tomskogo gosudarstvennogo universiteta. Matematika i mekhanika, no. 69 (2021): 114–26. http://dx.doi.org/10.17223/19988621/69/9.

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The mathematical model and results of a numerical study of swirling turbulent air flow characteristics in a semi-closed cylinder rotating around a symmetry axis are presented. A physical and mathematical model is used to describe aerodynamics of the stationary isothermal axisymmetric swirling flow, which includes the Navier-Stokes equations in cylindrical coordinates. The study of turbulence characteristics is carried out using the composite model Menter SST (Shear Stress Transport). The numerical solution is obtained using a chess grid. Nodes for axial and radial velocity components are located in the middle of the control volume faces for scalar quantities. Calculations are performed on a grid with 2000 and 1700 nodes in the axial and radial directions, respectively. The grid refinement is performed near the walls and in the areas with large velocity gradients. The calculated results show that the main grid refinement by 2 times in the axial and radial coordinates leads to a change in the values of the main variables by less than 1%. It is shown that the flow structure is determined by the rotational speed and cylinder height. Analyzing the calculated results, the ratio of the cylinder height to the angular velocity of the cylinder rotation is obtained, which ensures the formation of a quasi-solid rotation zone in the near-edge region.

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Ledezma, G. A., A. Folch, S. N. Bhatia, U. J. Balis, M. L. Yarmush, and M. Toner. "Numerical Model of Fluid Flow and Oxygen Transport in a Radial-Flow Microchannel Containing Hepatocytes." Journal of Biomechanical Engineering 121, no. 1 (February 1, 1999): 58–64. http://dx.doi.org/10.1115/1.2798043.

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The incorporation of monolayers of cultured hepatocytes into an extracorporeal perfusion system has become a promising approach for the development of a temporary bioartificial liver (BAL) support system. In this paper we present a numerical investigation of the oxygen tension, shear stress, and pressure drop in a bioreactor for a BAL composed of plasma-perfused chambers containing monolayers of porcine hepatocytes. The chambers consist of microfabricated parallel disks with center-to-edge radial flow. The oxygen uptake rate (OUR), measured in vitro for porcine hepatocytes, was curve-fitted using Michaelis–Menten kinetics for simulation of the oxygen concentration profile. The effect of different parameters that may influence the oxygen transport inside the chambers, such as the plasma flow rate, the chamber height, the initial oxygen tension in the perfused plasma, the OUR, and Km was investigated. We found that both the plasma flow rate and the initial oxygen tension may have an important effect upon oxygen transport. Increasing the flow rate and/or the inlet oxygen tension resulted in improved oxygen transport to cells in the radial-flow microchannels, and allowed significantly greater diameter reactor without oxygen limitation to the hepatocytes. In the range investigated in this paper (10 μm < H < 100 μm), and for a constant plasma flow rate, the chamber height, H, had a negligible effect on the oxygen transport to hepatocytes. On the contrary, it strongly affected the mechanical stress on the cells that is also crucial for the successful design of the BAL reactors. A twofold decrease in chamber height from 50 to 25 μm produced approximately a fivefold increase in maximal shear stress at the inlet of the reactor from 2 to 10 dyn/cm2. Further decrease in chamber height resulted in shear stress values that are physiologically unrealistic. Therefore, the channel height needs to be carefully chosen in a BAL design to avoid deleterious hydrodynamic effects on hepatocytes.

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Bekhit, A., and F. Popescu. "Numerical Investigation of the Shallow Water Effect on the Total Resistance, Vertical Motion and Wave Profile of a Container Ship Model." IOP Conference Series: Materials Science and Engineering 1182, no. 1 (October 1, 2021): 012005. http://dx.doi.org/10.1088/1757-899x/1182/1/012005.

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Abstract A ship sailing in shallow water is affected by the interaction between the moving hull and the seabed in different forms such as: significant increase in total resistance, increase in the sinkage and trim that may result in squatting effect, a change in wave pattern and increased wave amplitude, a change in the propeller wake field and an altered propeller and manoeuvring performance. In order to investigate the influence of shallow water on a container ship that is assumed to be subjected to work in different water depths, the KRISO container ship model is analysed in both deep and shallow water, with a special focus on the change in resistance, vertical motion and wave profile. A viscous flow simulation is performed first to predict the ship performance in deep water and the results are compared with the experimental data that are available in the public domain. Then, the critical shallow water condition is investigated and the obtained results are compared against those formerly obtained in deep water. The numerical simulations are performed using the viscous flow solver ISIS-CFD of the FINETM/Marine software provided by NUMECA. The solver is based on the finite volume method to build the spatial discretization of the transport equation in order to solve the Reynolds-Averaged Navier-Stokes (RANS) equations. Closure to turbulence is achieved using the Menter Shear Stress Transport (K-ω SST) model, while the free-surface is captured through an air-water interface based on the Volume of Fluid (VOF) method. The comparison between the numerically obtained results and the available EFD data showed a satisfactory congruence.

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Lobanov, I. E. "MODELING HEAT EXCHANGE DEPENDING ON THE PRANDTL NUMBER FOR VARIOUS GEOMETRIC AND REGIME PARAMETERS." Herald of Dagestan State Technical University. Technical Sciences 46, no. 4 (January 2, 2020): 91–101. http://dx.doi.org/10.21822/2073-6185-2019-46-4-91-101.

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Objectives. The aim is to study the dependency of the distribution of integral heat transfer during turbulent convective heat transfer in a pipe with a sequence of periodic protrusions of semicircular geometry on the Prandtl number using the calculation method based on a numerical solution of the system of Reynolds equations closed using the Menter’s shear stress transport model and the energy equation on different-sized intersecting structured grids.Method. A calculation was carried out on the basis of a theoretical method based on the solution of the Reynolds equations by factored finite-volume method closed with the help of the Menter shear stress transport model, as well as the energy equation on different-scaled intersecting structured grids (fast composite mesh method (FCOM)).Results. The calculations performed in the work showed that with an increase in the Prandtl number at small Reynolds numbers, there is an initial noticeable increase in the relative heat transfer. With additional increase in the Prandtl number, the relative heat transfer changes less: for small steps, it increases; for median steps it is almost stabilised, while for large steps it declines insignificantly. At large Reynolds numbers, the relative heat transfer decreases with an increase in the Prandtl number followed by its further stabilisation.Conclusion. The study analyses the calculated dependencies of the relative heat transfer on the Pr Prandtl number for various values of the relative h/D height of the turbulator, the relative t/D pitch between the turbulators and for various values of the Re Reynolds number. Qualitative and quantitative changes in calculated parameters are described all other things being equal. The analytical substantiation of the obtained calculation laws is that the height of the turbuliser is less for small Reynolds numbers, while for large Reynolds numbers, it is less than the height of the wall layer. Consequently, only the core of the flow is turbulised, which results in an increase in hydroresistance and a decrease in heat transfer. In the work on the basis of limited calculation material, a tangible decrease in the level of heat transfer intensification for small Prandtl numbers is theoretically confirmed. The obtained results of intensified heat transfer in the region of low Prandtl numbers substantiate the promising development of research in this direction. The theoretical data obtained in the work have determined the laws of relative heat transfer across a wide range of Prandtl numbers, including in those areas where experimental material does not currently exist.

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Shih, Tom I. P., Yu-Liang Lin, and Mark A. Stephens. "Fluid Flow and Heat Transfer in an Internal Coolant Passage." International Journal of Rotating Machinery 7, no. 5 (2001): 351–64. http://dx.doi.org/10.1155/s1023621x0100029x.

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Computations were performed to study the three-dimensional flow and heat transfer in a U-shaped duct of square cross section with inclined ribs on two opposite walls under rotating and non-rotating conditions. Two extreme limits in the Reynolds number (25,000 and 350,000) were investigated. The rotation numbers investigated are 0, 0.24, and 0.039. Results show rotation and the bend to reinforce secondary flows that align with it and to retard those that do not. Rotation was found to affect significantly the flow and heat transfer in the bend even at a very high Reynolds number of 350,000 and a very low Rotation number of 0:039. When there is no rotation, the flow and heat transfer in the bend were dominated by rib-induced secondary flows at the high Reynolds number limit and by bend-induced pressure-gradients at the low Reynolds number limit. Long streaks of reduced surface heat transfer occur in the bend at locations where streamlines from two contiguous secondary flows merge and then flow away from the surface. The location and size of these streaks varied markedly with Reynolds and rotation numbers.This computational study is based on the ensemble-averaged conservation equations of mass, momentum (compressible Navier-Stokes), and energy. Turbulence is modelled by the low-Reynolds shear-stress transport (SST) model of Menter. Solutions were generated by using a cell-centered, finite-volume method, that is based on second-order accurate flux-difference splitting and a diagonalized alternating-direction implicit scheme with local time-stepping and V-cycle multigrid.

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Isaev, S. A., P. A. Baranov, A. G. Sudakov, and I. A. Popov. "Verification of the standard model of shear stress transport and its modified version that takes into account the streamline curvature and estimation of the applicability of the Menter combined boundary conditions in calculating the ultralow profile drag for an optimally configured cylinder–coaxial disk arrangement." Technical Physics 61, no. 8 (August 2016): 1152–61. http://dx.doi.org/10.1134/s1063784216080120.

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Sana, Ahmad, and Hitoshi Tanaka. "NUMERICAL MODELING OF A TURBULENT BOTTOM BOUNDARY LAYER UNDER SOLITARY WAVES ON A SMOOTH SURFACE." Coastal Engineering Proceedings, no. 36 (December 30, 2018): 26. http://dx.doi.org/10.9753/icce.v36.currents.26.

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A number of studies on bottom boundary layers under sinusoidal and cnoidal waves were carried out in the past owing to the role of bottom shear stress on coastal sediment movement. In recent years, the bottom boundary layers under long waves have attracted considerable attention due to the occurrence of huge tsunamis and corresponding sediment movement. In the present study two-equation turbulent models proposed by Menter(1994) have been applied to a bottom boundary layer under solitary waves. A comparison has been made for cross-stream velocity profile and other turbulence properties in x-direction.

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Tarbell, John M. "Shear stress and the endothelial transport barrier." Cardiovascular Research 87, no. 2 (June 12, 2010): 320–30. http://dx.doi.org/10.1093/cvr/cvq146.

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Vitillo, F., C. Galati, L. Cachon, E. Laroche, and P. Millan. "An anisotropic shear stress transport (ASST) model formulation." Computers & Mathematics with Applications 70, no. 9 (November 2015): 2238–51. http://dx.doi.org/10.1016/j.camwa.2015.08.023.

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Vongvisessomjai, Suphat. "TIME-DEPENDENT WAVE SHEAR STRESS." Coastal Engineering Proceedings 1, no. 21 (January 29, 1988): 81. http://dx.doi.org/10.9753/icce.v21.81.

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A knowledge of bed shear stress induced by waves is required to understand dynamic processes of nearshore morphologies as a results of sediment transport. However, the information on the stress is still incomplete due to lack of measured data. The study analyzes the unsteady horizontally averaged shear stresses measured over mobile beds in a water tunnel. It is found from the analysis that the presence of the third and fifth harmonics in the shear stress is in good agreement with the measured concentration of suspended sediments.

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Adams, David L., and Brett C. Eaton. "A comparison of 1D and 2D bedload transport functions under high excess shear stress conditions in laterally constrained gravel-bed rivers: a laboratory study." Earth Surface Dynamics 10, no. 5 (September 15, 2022): 895–907. http://dx.doi.org/10.5194/esurf-10-895-2022.

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Abstract. Channel processes under high-magnitude flow events are of central interest to river science and management as they may produce large volumes of sediment transport and geomorphic work. However, bedload transport processes under these conditions are poorly understood due to data collection limitations and the prevalence of physical models that restrict feedbacks surrounding morphologic adjustment. The extension of mechanistic bedload transport equations to gravel-bed rivers has emphasised the importance of variance in both entraining (shear stress) and resisting (grain size) forces, especially at low excess shear stresses. Using a fixed-bank laboratory model, we tested the hypothesis that bedload transport in rivers collapses to a more simple function (i.e. with mean shear stress and median grain size) under high excess shear stress conditions. Bedload transport was well explained by the mean shear stress (1D approach) calculated using the depth–slope product. Numerically modelling shear stress to account for the variance in shear stress (2D) did not substantially improve the correlation. Critical dimensionless shear stress values were back-calculated and were higher for the 2D approach compared to the 1D. This result suggests that 2D critical values account for the relatively greater influence of high shear stresses, whereas the 1D approach assumes that the mean shear stress is sufficient to mobilise the median grain size. While the 2D approach may have a stronger conceptual basis, the 1D approach performs unreasonably well under high excess shear stress conditions. Further work is required to substantiate these findings in laterally adjustable channels.

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Kim, Sang Dug, and Dong Joo Song. "Modified Shear-Stress Transport Turbulence Model for Supersonic Flows." Journal of Aircraft 42, no. 5 (September 2005): 1118–25. http://dx.doi.org/10.2514/1.10223.

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TADA, Shigeru, Hirokazu OZONO, and Ken OKAZAKI. "Interstitial shear stress affects macromolecules transport in arterial walls." Proceedings of the Thermal Engineering Conference 2004 (2004): 399–400. http://dx.doi.org/10.1299/jsmeted.2004.399.

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Atkinson, Joseph F., Athol D. Abrahams, Chitra Krishnan, and Gang Li. "Shear stress partitioning and sediment transport by overland flow." Journal of Hydraulic Research 38, no. 1 (January 2000): 37–40. http://dx.doi.org/10.1080/00221680009498356.

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Chakravarthy, Srinivasa R., and Todd D. Giorgio. "Shear stress-facilitated calcium ion transport across lipid bilayers." Biochimica et Biophysica Acta (BBA) - Biomembranes 1112, no. 2 (December 1992): 197–204. http://dx.doi.org/10.1016/0005-2736(92)90392-y.

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Lockwood, Kenneth, Patrick Grover, and Ana Maria Ferreira da Silva. "Quantification of bed-load transport over dunes." E3S Web of Conferences 40 (2018): 02010. http://dx.doi.org/10.1051/e3sconf/20184002010.

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There is disagreement in the literature as to whether a shear stress-based approach can be used to accurately predict sediment transport over dunes. This study aims to address this disagreement. To this end, use is made of an experiment involving the study of naturally formed, fully developed dunes produced in a laboratory flume. The bed shear stress is estimated through a combination of velocity, Reynolds stress measurements, and results of a CFD RANS rough wall model. The validity of using Bagnold’s equation to predict the bed-load rate is subsequently analyzed. In contrast to what has been previously suggested by some authors, it is found from the present experiment that the bed-load rate correlates well with the bed shear stress, and that Bagnold’s equation yields realistic values of the bed-load rate over the stoss side of the dune downstream of the reattachment point. This work also highlights the difficulties in reliably estimating the bed shear stress in complex flows. Such difficulties are overcome in this paper through a combination of flow velocity measurements and modeled results.

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Monsalve, Angel, Catalina Segura, Nicole Hucke, and Scott Katz. "A bed load transport equation based on the spatial distribution of shear stress – Oak Creek revisited." Earth Surface Dynamics 8, no. 3 (September 29, 2020): 825–39. http://dx.doi.org/10.5194/esurf-8-825-2020.

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Abstract. Bed load transport formulations for gravel-bed rivers are often based on reach-averaged shear stress values. However, the complexity of the flow field in these systems results in wide distributions of shear stress, whose effects on bed load transport are not well captured by the frequently used equations, leading to inaccurate estimates of sediment transport. Here, we modified a subsurface-based bed load transport equation to include the complete distributions of shear stress generated by a given flow within a reach. The equation was calibrated and verified using bed load data measured at Oak Creek, OR. The spatially variable flow field characterization was obtained using a two-dimensional flow model calibrated over a wide range of flows between 0.1 and 1.0 of bankfull discharge. The shape of the distributions of shear stress was remarkably similar across different discharge levels, which allowed it to be parameterized in terms of discharge using a gamma function. When discharge is high enough to mobilize the pavement layer (1.0 m3 s−1 in Oak Creek), the proposed transport equation had a similar performance to the original formulation based on reach-averaged shear stress values. In addition, the proposed equation predicts bed load transport rates for lower flows when the pavement layer is still present because it accounts for bed load transport occurring in a small fraction of the channel bed that experiences high values of shear stress. This is an improvement over the original equation, which fails to estimate this bed load flux by relying solely on reach-average shear stress values.

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Podryabinkin, Evgeny, and Valeriy Rudyak. "Modeling of Turbulent Flows Through the Annular Channel with Eccentricity and Rotating Inner Cilinder." Siberian Journal of Physics 7, no. 4 (December 1, 2012): 79–86. http://dx.doi.org/10.54362/1818-7919-2012-7-4-79-86.

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In this paper fully developed turbulent flows of Newtonian fluid in cylindrical annulus with eccentricity and rotating inner cylinder has been systematically studied. Modeling has been performed on the base of Menter Shear Transport model of turbulence in a wide range of Reynolds numbers, eccentricity, and radii ratio. As the result dependencies of flow field and pressure drop along the channel on geometrical and flow parameters have been found. It was shown that flow characteristics and dependence of the pressure drop are determined by which flow axial or rotational dominates and caused generation of turbulence. When rotational flow dominates the dependence of the pressure drop is almost linear. When axial flow dominates rotation practically has no impact on the pressure drop in concentric annulus. Appearance of the reverse flow in eccentric channel has a major impact on the pressure drop. In case when rotational flow dominates, appearance of the reverse flow is accompanied by threshold flow restructuring at some critical value of eccentricity. A correlation for determination of the pressure drop in various regimes has been developed for the case of concentric annulus

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Podryabinkin, Evgeny, and Valeriy Rudyak. "Modeling of Turbulent Flows Through the Annular Channel with Eccentricity and Rotating Inner Cilinder." Siberian Journal of Physics 7, no. 4 (December 1, 2012): 79–86. http://dx.doi.org/10.54362/10.54362/1818-7919-2012-7-4-79-86.

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In this paper fully developed turbulent flows of Newtonian fluid in cylindrical annulus with eccentricity and rotating inner cylinder has been systematically studied. Modeling has been performed on the base of Menter Shear Transport model of turbulence in a wide range of Reynolds numbers, eccentricity, and radii ratio. As the result dependencies of flow field and pressure drop along the channel on geometrical and flow parameters have been found. It was shown that flow characteristics and dependence of the pressure drop are determined by which flow axial or rotational dominates and caused generation of turbulence. When rotational flow dominates the dependence of the pressure drop is almost linear. When axial flow dominates rotation practically has no impact on the pressure drop in concentric annulus. Appearance of the reverse flow in eccentric channel has a major impact on the pressure drop. In case when rotational flow dominates, appearance of the reverse flow is accompanied by threshold flow restructuring at some critical value of eccentricity. A correlation for determination of the pressure drop in various regimes has been developed for the case of concentric annulus

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Sun, Wei, and Liping Xu. "Improvement of corner separation prediction using an explicit non-linear RANS closure." Journal of the Global Power and Propulsion Society 5 (April 7, 2021): 50–65. http://dx.doi.org/10.33737/jgpps/133913.

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In this paper, an investigation into the effect of explicit non-linear turbulence modelling on anisotropic turbulence flows is presented. Such anisotropic turbulence flows are typified in the corner separations in turbomachinery. The commonly used Reynolds-Averaged Navier-Stokes (RANS) turbulence closures, in which the Reynolds stress tensor is modelled by the Boussinesq (linear) constitutive relation with the mean strain-rate tensor, often struggle to predict corner separation with reasonable accuracy. The physical reason for this modelling deficiency is partially attributable to the Boussinesq hypothesis which does not count for the turbulence anisotropy, whilst in a corner separation, the flow is subject to three-dimensional (3D) shear and the effects due to turbulence anisotropy may not be ignored. In light of this, an explicit non-linear Reynolds stress-strain constitutive relation developed by Menter et al. is adopted as a modification of the Reynolds-stress anisotropy. Coupled with the Menter’s hybrid "k-ω" ⁄"k-ε" turbulence model, this non-linear constitutive relation gives significantly improved predictions for the corner separation flows within a compressor cascade, at both the design and off-design flow conditions. The mean vorticity field are studied to further investigate the physical reasons for these improvements, highlighting its potential for the widespread applications in the corner separation prediction.

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McLean, S. R., S. R. Wolfe, and J. M. Nelson. "Predicting Boundary Shear Stress and Sediment Transport over Bed Forms." Journal of Hydraulic Engineering 125, no. 7 (July 1999): 725–36. http://dx.doi.org/10.1061/(asce)0733-9429(1999)125:7(725).

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Nielsen, Peter. "Shear stress and sediment transport calculations for swash zone modelling." Coastal Engineering 45, no. 1 (March 2002): 53–60. http://dx.doi.org/10.1016/s0378-3839(01)00036-9.

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Le Bouteiller, Caroline, and J. G. Venditti. "Sediment transport and shear stress partitioning in a vegetated flow." Water Resources Research 51, no. 4 (April 2015): 2901–22. http://dx.doi.org/10.1002/2014wr015825.

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Okiy, Karinate Valentine. "A Comparative Analysis of Turbulence Models Utilised for the Prediction of Turbulent Airflow through a Sudden Expansion." International Journal of Engineering Research in Africa 16 (June 2015): 64–78. http://dx.doi.org/10.4028/www.scientific.net/jera.16.64.

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The turbulent airflow in a circular duct with sudden expansion was investigated utilizing three turbulence models. The turbulence models chosen are: the k-epsilon model, the shear stress transport model and the Reynolds-stress model. The performance of the models was investigated with respect to the flow parameter-recirculation length. The turbulent kinetic energy and velocity predictions were compared between the turbulence models and with experimental data, then interpreted on the basis of the recirculation length. From the results, the shear stress transport model predictions of recirculation length had the closest agreement with the experimental result compared to the other model. Likewise, the convergence rate for the shear stress transport model was reasonable compared to that of the Reynolds model which has the slowest convergence rate. In light of these findings, the shear stress transport model was discovered to be the most appropriate for the investigation of turbulent air flow in a circular duct with sudden expansion. Keywords: Turbulence, recirculation length, sudden expansion, Turbulence models.

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Boldock, Luke, Amanda Inzoli, Silvia Bonardelli, Sarah Hsiao, Alberto Marzo, Andrew Narracott, Julian Gunn, et al. "Integrating particle tracking with computational fluid dynamics to assess haemodynamic perturbation by coronary artery stents." PLOS ONE 17, no. 7 (July 28, 2022): e0271469. http://dx.doi.org/10.1371/journal.pone.0271469.

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Aims Coronary artery stents have profound effects on arterial function by altering fluid flow mass transport and wall shear stress. We developed a new integrated methodology to analyse the effects of stents on mass transport and shear stress to inform the design of haemodynamically-favourable stents. Methods and results Stents were deployed in model vessels followed by tracking of fluorescent particles under flow. Parallel analyses involved high-resolution micro-computed tomography scanning followed by computational fluid dynamics simulations to assess wall shear stress distribution. Several stent designs were analysed to assess whether the workflow was robust for diverse strut geometries. Stents had striking effects on fluid flow streamlines, flow separation or funnelling, and the accumulation of particles at areas of complex geometry that were tightly coupled to stent shape. CFD analysis revealed that stents had a major influence on wall shear stress magnitude, direction and distribution and this was highly sensitive to geometry. Conclusions Integration of particle tracking with CFD allows assessment of fluid flow and shear stress in stented arteries in unprecedented detail. Deleterious flow perturbations, such as accumulation of particles at struts and non-physiological shear stress, were highly sensitive to individual stent geometry. Novel designs for stents should be tested for mass transport and shear stress which are important effectors of vascular health and repair.

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Liu, Jing Yuan, and Wen Qiang Cheng. "An Improved Shear Stress Transport(SST) Model for High Speed Flows." Applied Mechanics and Materials 229-231 (November 2012): 625–29. http://dx.doi.org/10.4028/www.scientific.net/amm.229-231.625.

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An improved Shear Stress Transport(SST) model, which allows for the compressible corrections, is proposed in this study. Numerical scheme was established by taking advantage of the improved Total Variation Diminishing (TVD) scheme and by applying implicit scheme to the negative source terms of the turbulence model. Hypersonic flat-plate boundary-layer flows and hypersonic compression ramp flows marked with separation, reattachment and shock/boundary-layer interactions are then computed. The comparisons between the computational results, the experimental results and the semi-empirical formulations show that the compressible correction term of the SST turbulence model is the scalar product of the weighted density average of the turbulent fluctuating velocity and the pressure gradients of the average flow field correlation quantities. In addition, for flow with separation and without separation, calculation results of wall pressures, friction coefficients and wall heat transfer rate distributions using the improved model and established scheme agree better with the experimental results than that using the original SST model.

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Hanawa, Toshiyuki, Kenji Ikezawa, Mariko Ikeda, and Kazuo Tanishita. "2A23 Effect of Shear Stress for intracellular Transport of Endothelial Cells." Proceedings of the JSME Bioengineering Conference and Seminar 2001.12 (2001): 141–42. http://dx.doi.org/10.1299/jsmebs.2001.12.0_141.

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Nielsen, Peter, and David P. Callaghan. "Shear stress and sediment transport calculations for sheet flow under waves." Coastal Engineering 47, no. 3 (January 2003): 347–54. http://dx.doi.org/10.1016/s0378-3839(02)00141-2.

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Nollert, M. U., S. L. Diamond, and L. V. McIntire. "Hydrodynamic shear stress and mass transport modulation of endothelial cell metabolism." Biotechnology and Bioengineering 38, no. 6 (September 1991): 588–602. http://dx.doi.org/10.1002/bit.260380605.

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Kiraga and Popek. "Bed Shear Stress Influence on Local Scour Geometry Properties in Various Flume Development Conditions." Water 11, no. 11 (November 8, 2019): 2346. http://dx.doi.org/10.3390/w11112346.

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Numerous approaches in sediment mobility studies highlighted the key meaning of channel roughness, which results not only from bed material granulation but also from various bed forms presence, caused by continuous sediment transport. Those forms are strictly connected with the intensity of particle transport, and they eventuate from bed shear stress. The present paper comprised of local scours geometric dimensions research in three variants of lengthwise development of laboratory flume in various hydraulic properties, both in “clear-water” and “live-bed” conditions of sediment movement. Lots of measurements of the bed conformation were executed using the LiDAR device, marked by a very precise three-dimensional shape description. The influence of the bed shear stress downstream model on scours hole dimensions of water structure was investigated as one of the key factors that impact the sediment transport intensity. A significant database of 39 experimental series, lasting averagely 8 hours, was a foundation for delineating functional correlations between bed shear stress-and-critical shear stress ratio and geometry properties of local scours in various flume development cases. In the scope of mutual influence of bed shear stress and water depth, high correlation coefficients were attained, indicating very good and good functional correlations. Also, the influence of bed shear stress and the total length of the scour demonstrated a high correlation coefficient.

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Panigrahi, P. K., and S. Acharya. "Mechanisms of Turbulence Transport in a Turbine Blade Coolant Passage With a Rib Turbulator." Journal of Turbomachinery 121, no. 1 (January 1, 1999): 152–59. http://dx.doi.org/10.1115/1.2841224.

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This paper provides detailed measurements of the flow in a ribbed coolant passage, and attempts to delineate the important mechanisms that contribute to the production of turbulent shear stress and the normal stresses. It is shown that the separated flow behind the rib is dictated by large-scale structures, and that the dynamics of the large-scale structures, associated with sweep, ejection, and inward and outward interactions, all play an important role in the production of the turbulent shear stress. Unlike the turbulent boundary layer, in a separated shear flow past the rib, the inward and outward interaction terms are both important, accounting for a negative stress production that is nearly half of the positive stress produced by the ejection and sweep mechanisms. It is further shown that the shear layer wake persists well past the re-attachment location of the shear layer, implying that the flow between ribbed passages never recovers to that of a turbulent boundary layer. Therefore, even past re-attachment, the use of statistical turbulence models that ignore coherent structure dynamics is inappropriate.

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Roberts, Jesse D., Richard A. Jepsen, and Scott C. James. "Measurements of Sediment Erosion and Transport with the Adjustable Shear Stress Erosion and Transport Flume." Journal of Hydraulic Engineering 129, no. 11 (November 2003): 862–71. http://dx.doi.org/10.1061/(asce)0733-9429(2003)129:11(862).

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Wei, Yanzhou. "Cross-Shelf Circulation Induced by the Kuroshio Shear Stress in the East China Sea." Journal of Physical Oceanography 48, no. 7 (July 2018): 1479–93. http://dx.doi.org/10.1175/jpo-d-17-0204.1.

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AbstractThis study solves two-dimensional (cross-shelf and depth directions) steady-state nonlinear primitive equations to infer the cross-shelf circulation induced by the Kuroshio shear stress in the East China Sea (ECS). The Kuroshio velocity data are estimated from hydrographic observations at the PN section in the ECS. Nonlinear momentum equations are solved using an iterative approach in a terrain-following coordinate system, which helps to adequately take into account the boundary conditions over complex topography. The vertical shear stress of the Kuroshio is shown to induce two offshore transport pathways over the continental shelf, which are related to the structure of the interior geostrophic current and bottom Ekman transport, respectively. As a result of the vertical shear stress, an upwelling is induced above the bottom Ekman layer on the continental slope. The horizontal shear stress of the Kuroshio has the effect of inducing onshore transport at the flow core. The advection terms in the primitive equations are found to amplify the cross-shelf velocity solved from the linear equations. This study reveals that the Kuroshio has a substantial effect on the cross-shelf circulation and that it might drive multiple transport pathways.

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Wisitsorasak, Apiwat, and Peter G. Wolynes. "Dynamical theory of shear bands in structural glasses." Proceedings of the National Academy of Sciences 114, no. 6 (January 20, 2017): 1287–92. http://dx.doi.org/10.1073/pnas.1620399114.

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The heterogeneous elastoplastic deformation of structural glasses is explored using the framework of the random first-order transition theory of the glass transition along with an extended mode-coupling theory that includes activated events. The theory involves coupling the continuum elastic theory of strain transport with mobility generation and transport as described in the theory of glass aging and rejuvenation. Fluctuations that arise from the generation and transport of mobility, fictive temperature, and stress are treated explicitly. We examine the nonlinear flow of a glass under deformation at finite strain rate. The interplay among the fluctuating fields leads to the spatially heterogeneous dislocation of the particles in the glass, i.e., the appearance of shear bands of the type observed in metallic glasses deforming under mechanical stress.

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DeMaio, Lucas, Yong S. Chang, Thomas W. Gardner, John M. Tarbell, and David A. Antonetti. "Shear stress regulates occludin content and phosphorylation." American Journal of Physiology-Heart and Circulatory Physiology 281, no. 1 (July 1, 2001): H105—H113. http://dx.doi.org/10.1152/ajpheart.2001.281.1.h105.

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Previous studies determined that shear stress imposed on bovine aortic endothelial cell (BAEC) monolayers increased the hydraulic conductivity ( L P); however, the mechanism by which shear stress increases L Premains unknown. This study tested the hypothesis that shear stress regulates paracellular transport by altering the expression and phosphorylation state of the tight junction protein occludin. The effect of shear stress on occludin content was examined by Western blot analysis. Ten dyn/cm2 significantly reduced occludin content in a time-dependent manner such that after a 3 h exposure to shear, occludin content decreased to 44% of control. Twenty dyn/cm2 decreased occludin content to 50% of control and increased L P by 4.7-fold after 3 h. Occludin expression and L P depend on tyrosine kinase activity because erbstatin A (10 μM) attenuated both the shear-induced decrease in occludin content and increase in L P. Shear stress increased occludin phosphorylation after 5 min, 15 min, and 3 h exposures. The shear-induced increase in occludin phosphorylation was attenuated with dibutyryl (DB) cAMP (1 mM), a reagent previously shown to reverse the shear-induced increase in L P. We conclude that shear stress rapidly (≤5 min) increases occludin phosphorylation and significantly decreases the expression of occludin over 1–4 h. Alterations in the occludin phosphorylation state and occludin total content are potential mechanisms by which shear stress increases L P.

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Nering, Konrad, and Krzysztof Nering. "Validation of Modified Algebraic Model during Transitional Flow in HVAC Duct." Energies 14, no. 13 (July 2, 2021): 3975. http://dx.doi.org/10.3390/en14133975.

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Airflow occurring in a ventilation duct is characterized by low velocity and hence low Reynolds number. In these conditions, either a laminar, transitional or turbulent flow will occur. Different flow conditions result in different values of the friction coefficient. To achieve the transitional flow in numerical simulation, a modified algebraic model for bypass transition (modified k−ω) was used. Numerical simulation was validated using Particle Tracking Velocimetry (PTV) in the circular channel. The modified algebraic model consists of only two partial differential equations, which leads to much faster calculation than the shear stress transport model. Results of the modified algebraic model are largely consistent with either the measurement and shear stress transport model considering laminar and transitional flow. Consistency slightly decreased in turbulent flow in relation to the model using shear stress transport method.

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Bernard, Peter S., and Martin A. Erinin. "Fluid particle dynamics and the non-local origin of the Reynolds shear stress." Journal of Fluid Mechanics 847 (May 23, 2018): 520–51. http://dx.doi.org/10.1017/jfm.2018.333.

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The causative factors leading to the Reynolds shear stress distribution in turbulent channel flow are analysed via a backward particle path analysis. It is found that the classical displacement transport mechanism, by which changes in the mean velocity field over a mixing time correlate with the wall-normal velocity, is the dominant source of Reynolds shear stress. Approximately 20 % of channel flow at any given time contains fluid motions that contribute to displacement transport. Much rarer events provide a small but non-negligible contribution to the Reynolds shear stress due to fluid particle accelerations and long-lived correlations deriving from structural features of the near-wall flow. The Reynolds shear stress in channel flow is shown to be a non-local phenomenon that is not conducive to description via a local model and particularly one depending directly on the local mean velocity gradient.

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Marty, Julien, and Cédric Uribe. "Impact of Underlying RANS Turbulence Models in Zonal Detached Eddy Simulation: Application to a Compressor Rotor." International Journal of Turbomachinery, Propulsion and Power 5, no. 3 (August 26, 2020): 22. http://dx.doi.org/10.3390/ijtpp5030022.

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The present study focuses on the impact of the underlying RANS turbulence model in the Zonal Detached Eddy Simulation (ZDES) method when used for secondary flow prediction. This is carried out in light of three issues commonly investigated for hybrid RANS/LES methods (detection and protection of attached boundary layer, emergence, and growth of resolved turbulent fluctuations and accurate prediction of separation front due to progressive adverse pressure gradient). The studied configuration is the first rotor of a high pressure compressor. Three different turbulence modelings (Spalart and Allmaras model (SA), Menter model with (SST) and without (BSL) shear stress correction) are assessed as ZDES underlying turbulence model and also as turbulence model of unsteady RANS simulations. Whatever the underlying turbulence model, the ZDES behaves well with respect to the first two issues as the boundary layers appear effectively shielded and the RANS-to-LES switch is close downstream of trailing edges and separation fronts leading to a quick LES treatment of wakes and shear layers. Both tip leakage and corner flows are strongly influenced by the Navier–Stokes resolution approach (unsteady RANS vs. ZDES) but the underlying turbulence modelling (SA vs. SST vs. BSL) impacts mainly the junction flow near the hub for both approaches. ZDES underlying turbulence model choice appear essential since it leads to quite different corner flow separation topologies and so to inversion of the downstream stagnation pressure radial gradient.

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Jia, Xiaomeng, Xihuan Sun, and Jiaorong Song. "Effect of Concentric Annular Gap Flow on Wall Shear Stress of Stationary Cylinder Pipe Vehicle under Different Reynolds Numbers." Mathematical Problems in Engineering 2020 (May 15, 2020): 1–19. http://dx.doi.org/10.1155/2020/1253652.

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The tube-contained raw material pipeline hydraulic transportation technology is an optimization and improvement of traditional hydraulic capsule pipeline (HCP) transport. It has the advantages of lower resource consumption, environmental protection, and less demand for human resources and has the ability to directly transport solids, liquids, and gases. The cylinder pipe vehicle is the core component of tube-contained raw material pipeline hydraulic transportation; its motion characteristics and energy consumption are affected by wall shear stress. When the cylinder pipe vehicle is stationary, the annular gap flow will affect the wall shear stress. This paper studies the wall shear stress and annular flow field distribution of a stationary cylinder pipe vehicle under different Reynolds numbers. The results show that as the Reynolds number increases, both the wall shear stress and the annular gap flow velocity show a gradually increasing trend. The wall shear stress and the velocity of the annular gap flow show some correlation, but there are differences in the trend of axial and circumferential wall shear stress along the length of the cylinder pipe vehicle. The research in this article will further improve the theoretical system of hydraulic conveyance of barrel-loading pipelines and provide a theoretical basis for the realization of industrial applications as soon as possible.

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Hämmerling, Mateusz, Paweł Zawadzki, Natalia Walczak, and Michał Wierzbicki. "The bed load transport in rivers. Part I: Start moving, shear stress." Acta Scientiarum Polonorum Formatio Circumiectus 13, no. 4 (February 2015): 109–20. http://dx.doi.org/10.15576/asp.fc/2014.13.4.109.

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Byggstoyl, S., and W. Kollmann. "Stress transport in the rotational and irrotational zones of turbulent shear flows." Physics of Fluids 29, no. 5 (1986): 1423. http://dx.doi.org/10.1063/1.865659.

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Bovens, S. M., N. Foin, N. O'Clery, K. Van Der Heiden, S. Cuhlmann, H. Carlsen, M. Barahona, P. C. Evans, and R. Krams. "Shear stress and nitric oxide transport affect NFkB dynamics in endothelial cells." European Heart Journal 34, suppl 1 (August 2, 2013): P582. http://dx.doi.org/10.1093/eurheartj/eht307.p582.

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Journal articles on the topic 'Menter Shear stress transport'

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