Articoli di riviste: "Shear flow effects"

1

Kuroda, Mitsutoshi. "Effects of Crystallographic Texture on Plastic Flow Localization". Key Engineering Materials 340-341 (giugno 2007): 211–16. http://dx.doi.org/10.4028/www.scientific.net/kem.340-341.211.

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In this study, effects of typical texture components observed in rolled aluminum alloy sheets (i.e. Copper, Brass, S, Cube and Goss texture components) on plastic flow localization are studied. The material response is described by a generalized Taylor-type polycrystal model, in which each grain is characterized in terms of an elastic-viscoplastic continuum slip constitutive relation. First, forming limits of thin sheet set by sheet necking are predicted using a Marciniak–Kuczynski (M–K-) type approach. It is shown that only the Cube texture component yields forming limits higher than that for a random texture in the biaxial stretch range. Next, three-dimensional shear band analyses are performed, using a three-dimensional version of M–K-type model, but the overall deformation mode is restricted to a plane strain state. From this simple model analysis, two important quantities regarding shear band formation are obtained: i.e. the critical strain at the onset of shear banding and the corresponding orientation of shear band. It is concluded that the Cube texture component is said to be a shear band free texture, while some texture components exhibit significantly low resistance to shear band formation. Finally, shear band developments in plane strain pure bending of sheet specimens with the typical textures are studied.

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2

Smith, Ronald. "Buoyancy effects in vertical shear dispersion". Journal of Fluid Mechanics 242 (settembre 1992): 371–86. http://dx.doi.org/10.1017/s0022112092002416.

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Density gradients modify the flow and hence the shear dispersion of one miscible fluid in another. A solution procedure is given for calculating the effects of weak buoyancy for vertical laminar parallel shear flows. A particular extrapolation to large buoyancy gives an exactly solvable nonlinear diffusion equation. For the particular case of vertical plane Poiseuille flow explicit formulae are derived for the flow, for the nonlinear shear dispersion coefficient and for the onset of instability. The exactly solvable model gives reasonably accurate results for the buoyancy-modified shear dispersion over a range from half to one-and-a-half times the non-buoyant value.

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Chiu, J. J., D. L. Wang, S. Chien, R. Skalak e S. Usami. "Effects of Disturbed Flow On Endothelial Cells". Journal of Biomechanical Engineering 120, n. 1 (1 febbraio 1998): 2–8. http://dx.doi.org/10.1115/1.2834303.

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Atherosclerotic lesions tend to localize at curvatures and branches of the arterial system, where the local flow is often disturbed and irregular (e.g., flow separation, recirculation, complex flow patterns, and nonuniform shear stress distributions). The effects of such flow conditions on cultured human umbilical vein endothelial cells (HUVECs) were studied in vitro by using a vertical-step flow channel (VSF). Detailed shear stress distributions and flow structures have been computed by using the finite volume method in a general curvilinear coordinate system. HUVECs in the reattachment areas with low shear stresses were generally rounded in shape. In contrast, the cells under higher shear stresses were significantly elongated and aligned with the flow direction, even for those in the area with reversed flow. When HUVECs were subjected to shearing in VSF, their actin stress fibers reorganized in association with the morphological changes. The rate of DNA synthesis in the vicinity of the flow reattachment area was higher than that in the laminar flow area. These in vitro experiments have provided data for the understanding of the in vivo responses of endothelial cells under complex flow environments found in regions of prevalence of atherosclerotic lesions.

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4

Murata, T., e T. W. Secomb. "Effects of shear rate on rouleau formation in simple shear flow". Biorheology 25, n. 1-2 (1 aprile 1988): 113–22. http://dx.doi.org/10.3233/bir-1988-251-218.

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Conway, Daniel E., Marcie R. Williams, Suzanne G. Eskin e Larry V. McIntire. "Endothelial cell responses to atheroprone flow are driven by two separate flow components: low time-average shear stress and fluid flow reversal". American Journal of Physiology-Heart and Circulatory Physiology 298, n. 2 (febbraio 2010): H367—H374. http://dx.doi.org/10.1152/ajpheart.00565.2009.

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To simulate the effects of shear stress in regions of the vasculature prone to developing atherosclerosis, we subjected human umbilical vein endothelial cells to reversing shear stress to mimic the hemodynamic conditions at the wall of the carotid sinus, a site of complex, reversing blood flow and commonly observed atherosclerosis. We compared the effects of reversing shear stress (time-average: 1 dyn/cm2, maximum: +11 dyn/cm2, minimum: −11 dyn/cm2, 1 Hz), arterial steady shear stress (15 dyn/cm2), and low steady shear stress (1 dyn/cm2) on gene expression, cell proliferation, and monocyte adhesiveness. Microarray analysis revealed that most differentially expressed genes were similarly regulated by all three shear stress regimens compared with static culture. Comparisons of the three shear stress regimens to each other identified 138 genes regulated by low average shear stress and 22 genes regulated by fluid reversal. Low average shear stress induced increased cell proliferation compared with high shear stress. Only reversing shear stress exposure induced monocyte adhesion. The adhesion of monocytes was partially inhibited by the incubation of endothelial cells with ICAM-1 blocking antibody. Increased heparan sulfate proteoglycan expression was observed on the surface of cells exposed to reversing shear stress. Heparinase III treatment significantly reduced monocyte adhesion. Our results suggest that low steady shear stress is the major impetus for differential gene expression and cell proliferation, whereas reversing flow regulates monocyte adhesion.

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Toppaladoddi, S., e J. S. Wettlaufer. "The combined effects of shear and buoyancy on phase boundary stability". Journal of Fluid Mechanics 868 (17 aprile 2019): 648–65. http://dx.doi.org/10.1017/jfm.2019.153.

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We study the effects of externally imposed shear and buoyancy driven flows on the stability of a solid–liquid interface. A linear stability analysis of shear and buoyancy-driven flow of a melt over its solid phase shows that buoyancy is the only destabilizing factor and that the regime of shear flow here, by inhibiting vertical motions and hence the upward heat flux, stabilizes the system. It is also shown that all perturbations to the solid–liquid interface decay at a very modest shear flow strength. However, at much larger shear-flow strength, where flow instabilities coupled with buoyancy might enhance vertical motions, a re-entrant instability may arise.

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Chen, Y. C., Y. Q. Qin, G. Y. Sun, G. Dong, Y. Xiao e Z. Lin. "Effects of radial electric field on kinetic ballooning mode in toroidal plasma". Physics of Plasmas 30, n. 2 (febbraio 2023): 022302. http://dx.doi.org/10.1063/5.0131294.

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Global gyrokinetic particle simulations show that the radial electric field ( Er) shear can suppress the kinetic ballooning mode (KBM) in a toroidal plasma. The linear KBM growth rate reaches a maximum when the toroidal rotation induced by the ion diamagnetic shear is canceled by the E × B flow shear. High toroidal-mode-number (high- n) KBMs are more sensitive to the Er shear than low- n KBMs. Nonlinear simulations find that both the Er shear and a self-generated zonal flow can reduce the nonlinear KBM saturation level with smaller particle and ion heat transport. Meanwhile, the zonal flow can weaken the suppressing effects of the Er shear on KBM nonlinear saturation amplitude. The radial correlation length of the turbulence is reduced by the Er shear and the zonal flow.

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Popova, A. V., O. V. Sheremetyeva, M. E. Bobrova e A. S. Perezhogin. "Non-local deformation effects in shear flows". Nonlinear Processes in Geophysics Discussions 2, n. 1 (21 gennaio 2015): 69–96. http://dx.doi.org/10.5194/npgd-2-69-2015.

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Abstract. The method for detection of clusters on the basis of event space–time dependence is classically applied for foreshock–mainshock–aftershock sequences for which event connectedness is generally accepted. In the paper, this approach is used to investigate the whole event catalogue of foreshock and aftershock sequences filtered from the events with small magnitudes, in which connected events are also determined. The space scale is extended due to the inclusion of the parameter of seismic event connectedness in the direction of dislocation shift that allows us to consider the obtained connected events as clusters in a shear flow. A statistical model of the shear flow was constructed by catalogue decomposition into timescales and space scales defined analytically. A modelling algorithm of the shear flow was developed and its stability to initial condition change was investigated. Shear flow structure and arising non-local deformation characteristics which may be the criteria for dynamic process activity in the considered subduction zone of the Kuril–Kamchatka island arc were analysed.

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Akao, Takumi, Tomoaki Watanabe e Koji Nagata. "Vertical confinement effects on a fully developed turbulent shear layer". Physics of Fluids 34, n. 5 (maggio 2022): 055129. http://dx.doi.org/10.1063/5.0090686.

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The effects of vertical confinement on a turbulent shear layer are investigated with large-eddy simulations of a freely developing shear layer (FSL) and a wall-confined shear layer (WSL) that develops between two horizontal walls. In the case of the WSL, the growth of the shear layer is inhibited by the walls. Once the walls prevent the development of the shear layer, highly anisotropic velocity fluctuations become prominent in the flow. These anisotropic velocity fluctuations are recognized as elongated large-scale structures (ELSS), whose streamwise length is much larger than the length scales in the other directions. Spectral analysis confirms that the turbulent kinetic energy is dominated by the ELSS, whose streamwise length grows continuously. A proper orthogonal decomposition can effectively extract a velocity component associated with the ELSS. The isotropy of the Reynolds stress tensor is changed by the presence of the ELSS. These changes in flow characteristics due to the ELSS are not observed in the FSL, where the shear layer thickness increases continuously. These behaviors of the WSL are consistent with those of stably stratified shear layers (SSSLs), where flow structures similar to ELSS also develop when the vertical flow development is confined by the stable stratification. The vertical confinement by the walls or stable stratification strengthens mean shear effects. The flow behavior at large scales in the WSL and SSSL is consistent with rapid distortion theory for turbulence subject to mean shear, suggesting that the development of ELSS is caused by the mean shear.

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Ayukawa, K., J. Ochi, G. Kawahara e T. Hirao. "Effects of shear rate on the flow around a square cylinder in a uniform shear flow". Journal of Wind Engineering and Industrial Aerodynamics 50 (dicembre 1993): 97–106. http://dx.doi.org/10.1016/0167-6105(93)90065-v.

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Qiu, Wei-Ping, Qinghua Hu, Nazareno Paolocci, Roy C. Ziegelstein e David A. Kass. "Differential effects of pulsatile versus steady flow on coronary endothelial membrane potential". American Journal of Physiology-Heart and Circulatory Physiology 285, n. 1 (luglio 2003): H341—H346. http://dx.doi.org/10.1152/ajpheart.01072.2002.

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Steady shear stress stimulates transient hyperpolarization coupled to calcium-sensitive potassium (KCa) channels and sustained depolarization linked to chloride-selective channels. Physiological flow is pulsatile not static, and whereas in vivo data suggest phasic shear stress may preferentially activate KCa channels, its differential effects on both currents remain largely unknown. To determine this interaction, coronary endothelial cells were cultured in glass capillary flow tubes, loaded with the voltage-sensitive dye bis-(1,3-dibutylbarbituric acid)trimethine oxonol, and exposed to constant or pulsatile shear stress. The latter was generated by a custom servoperfusion system employing physiological pressure and flow waveforms. Steady shear induced a sustained depolarization inhibited by the Cl- channel blocker DIDS. Even after exposure to steady flow, subsequent transition to pulsatile shear stress further stimulated DIDS-sensitive depolarization. DIDS pretreatment “unmasked” a pulsatile flow-induced hyperpolarization of which magnitude was further enhanced by nifedipine, which augments epoxygenase synthesis. Pulse-shear hyperpolarization was fully blocked by KCa channel inhibition (charybdotoxin + apamin), although these agents had no influence on membrane potential altered by steady flow. Thus KCa-dependent hyperpolarization is preferentially stimulated by pulsatile over steady flow, whereas both can stimulate Cl--dependent depolarization. This supports studies showing greater potency of pulsatile flow for triggering KCa-dependent vasorelaxation.

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Haury, Loren R., Hidekatsu Yamazaki e Eric C. Itsweire. "Effects of turbulent shear flow on zooplankton distribution". Deep Sea Research Part A. Oceanographic Research Papers 37, n. 3 (marzo 1990): 447–61. http://dx.doi.org/10.1016/0198-0149(90)90019-r.

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Tanaka, Kentaro G., Masaki Fujimoto e Iku Shinohara. "Physics of Magnetopause Reconnection: A Study of the Combined Effects of Density Asymmetry, Velocity Shear, and Guide Field". International Journal of Geophysics 2010 (2010): 1–17. http://dx.doi.org/10.1155/2010/202583.

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Magnetopause reconnection would be characterized by the density jump across the current sheet, the flow shear across the boundary, and nonzero guide field. While effects of each of these elements have been studied, the effects arising from the combination of these are still unexplored. Two-dimensional full-particle simulations show that the combination of shear flow and/or guide field with density asymmetry induces the sliding motion of theX-line along the magnetopause. The direction of theX-line motion is controlled either by the ion flow at theX-line when the shear flow effects dominate or by the electron flow at theX-line when the guide field effects dominate. The shear flow effects and the guide field effects may counteract each other in determining the direction of theX-line motion and, in the close proximity of the subsolar region where the flow is slow, theX-line motion can be opposite to the flow direction.

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Kim, Dokyum, Yongsam Kim e Sookkyung Lim. "Effects of swimming environment on bacterial motility". Physics of Fluids 34, n. 3 (marzo 2022): 031907. http://dx.doi.org/10.1063/5.0082768.

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Swimming trajectories of bacteria can be altered by environmental conditions, such as background flow and physical barriers, that limit the free swimming of bacteria. We present a comprehensive model of a bacterium that consists of a rod-shaped cell body and a flagellum which is composed of a motor, a hook, and a filament. The elastic flagellum is modeled based on the Kirchhoff rod theory, the cell body is considered to be a rigid body, and the hydrodynamic interaction of a bacterium near a wall is described by regularized Stokeslet formulation combined with the image system. We consider three environmental conditions: (1) a rigid surface is placed horizontally and there is no shear flow, (2) a shear fluid flow is present and the bacterium is near the rigid surface, and (3) while the bacterium is near the rigid surface and is under shear flow, an additional sidewall which is perpendicular to the rigid surface is placed. Each environmental state modifies the swimming behavior. For the first condition, there are two modes of motility, trap and escape, whether the bacterium stays near the surface or moves away from the surface as we vary the physical and geometrical properties of the model bacterium. For the second condition, there exists a threshold of shear rate that classifies the motion into two types of paths in which the bacterium takes either a periodic coil trajectory or a linear trajectory. For the last condition, the bacterium takes upstream motility along the sidewall for lower shear rates and downstream motility for larger shear flow rates.

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Jain, V. K., e B. K. Gupta. "Effects of Accelerated Tests on Shear Flow Stress in Machining". Journal of Engineering for Industry 109, n. 3 (1 agosto 1987): 206–12. http://dx.doi.org/10.1115/1.3187120.

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Facing and taper turning tests (also known as accelerated cutting tests) are commonly used for the evaluation of machinability of materials. Of late, it has been reported that instantaneous values of tool-chip interface temperature, tool wear, shear angle, etc, in longitudinal turning are different from the corresponding values in accelerated cutting. This effect has been attributed to shear strain acceleration phenomenon. Materials behavior during accelerated cutting changes in a manner different than that in longitudinal turning. To test this hypothesis, experiments have been conducted using HSS as tool material and mild steel as work material. It has been concluded that shear flow stress during accelerated cutting is governed by shear strain acceleration and its governing parameters. Shear flow stress value is highest during facing, lowest in taper turning and in between the two during longitudinal turning.

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Lee, M. "PP/LCP composites: effects of shear flow, extensional flow and nanofillers". Composites Science and Technology 63, n. 13 (ottobre 2003): 1921–29. http://dx.doi.org/10.1016/s0266-3538(03)00156-8.

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Varpe, Mahesh, e A. M. Pradeep. "Investigation of the Shear Flow Effect and Tip Clearance on a Low Speed Axial Flow Compressor Cascade". International Journal of Rotating Machinery 2013 (2013): 1–22. http://dx.doi.org/10.1155/2013/490543.

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This paper explores the effect of inlet shear flow on the tip leakage flow in an axial flow compressor cascade. A flow with a high shear rate is generated in the test section of an open circuit cascade wind tunnel by using a combination of screens with a prescribed solidity. It is observed that a stable shear flow of shear rate 1.33 is possible and has a gradual decay rate until 15 times the height of the shear flow generator downstream. The computational results obtained agree well with the available experimental data on the baseline configuration. The detailed numerical analysis shows that the tip clearance improves the blade loading near the tip through the promotion of favorable incidence by the tip leakage flow. The tip clearance shifts the centre of pressure on the blade surface towards the tip. It, however, has no effect on the distribution of end wall loss and deviation angle along the span up to 60% from the hub. In the presence of a shear inflow, the end wall effects are considerable. On the other hand, with a shear inflow, the effects of tip leakage flow are observed to be partly suppressed. The shear flow reduces the tip leakage losses substantially in terms of kinetic energy associated with it.

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Lee, Hong Woo, e Kyung Seok Oh. "Effects of Non-Associated Flow Rule on AHSS Shear Fracture". Key Engineering Materials 725 (dicembre 2016): 465–70. http://dx.doi.org/10.4028/www.scientific.net/kem.725.465.

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Recently, advanced high strength steels (AHSSs) have been widely applied to the structural parts of vehicles thanks to their good combination of strength and ductility. When one makes parts with AHSSs, however, fractures in sharp corners of the parts are frequently observed below forming limit, which is normally defined by strain based FLC(Forming Limit Curve). This phenomenon is well-known as “Shear Fracture”. Recent researches point out that additional numerical techniques should be considered in order to predict it accurately. Kim et al. [1] suggested that shear fracture can be predictable with continuum-based finite elements rather than conventional shell elements, and more constitutive informations for large strain thermo-mechanical simulation are needed to improve accuracy. Luo and Wierzbicki [2] showed that shear fracutre in stretch-bending test can be fully characterized by proposed MMC(Modified Mohr-Coulomb). This paper shows that solid-shell approach based on hyper-elastoplastic material model enables one to properly predict shear fracture pheonomenon without any special failure criteria. Furthermore, the effects of non-associated flow rule on shear fracture will be also discussed with several numerical examples.

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Dacus, Michael, Mahmud Kamal Raihan, Micah Baghdady, Chase Gabbard, Sen Wu, Joshua B. Bostwick, Yongxin Song e Xiangchun Xuan. "Surfactant effects on microfluidic extensional flow of water and polymer solutions". Physics of Fluids 34, n. 3 (marzo 2022): 032006. http://dx.doi.org/10.1063/5.0085967.

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Surfactants are often added to particle suspensions in the flow of Newtonian or non-Newtonian fluids for the purpose of reducing particle-particle aggregation and particle-wall adhesion. However, the impact on the flow behavior of such surfactant additions is often overlooked. We experimentally investigate the effect of the addition of a frequently used neutral surfactant, Tween 20, at the concentration pertaining to microfluidic applications on the entry flow of water and three common polymer solutions through a planar cavity microchannel. We find that the addition of Tween 20 has no significant influence on the shear viscosity or extensional flow of Newtonian water and Boger polyethylene oxide solution. However, such a surfactant addition reduces both the shear viscosity and shear-thinning behavior of xanthan gum and polyacrylamide solutions that each exhibit a strong shear-thinning effect. It also stabilizes the cavity flow and delays the onset of flow instability in both cases. The findings of this work can directly benefit microfluidic applications of particle and cell manipulation in Newtonian and non-Newtonian fluids.

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Aguirre, Roberto C., Jennifer C. Nathman e Haris C. Catrakis. "Flow Geometry Effects on the Turbulent Mixing Efficiency". Journal of Fluids Engineering 128, n. 4 (9 febbraio 2006): 874–79. http://dx.doi.org/10.1115/1.2201696.

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Flow geometry effects are examined on the turbulent mixing efficiency quantified as the mixture fraction. Two different flow geometries are compared at similar Reynolds numbers, Schmidt numbers, and growth rates, with fully developed turbulence conditions. The two geometries are the round jet and the single-stream planar shear layer. At the flow conditions examined, the jet exhibits an ensemble-averaged mixing efficiency which is approximately double the value for the shear layer. This substantial difference is explained fluid mechanically in terms of the distinct large-scale entrainment and mixing-initiation environments and is therefore directly due to flow geometry effects.

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Bryan, Robert M., Sean P. Marrelli, Marie L. Steenberg, Lisa A. Schildmeyer e T. David Johnson. "Effects of luminal shear stress on cerebral arteries and arterioles". American Journal of Physiology-Heart and Circulatory Physiology 280, n. 5 (1 maggio 2001): H2011—H2022. http://dx.doi.org/10.1152/ajpheart.2001.280.5.h2011.

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The effect of luminal shear stress was studied in cerebral arteries and arterioles. Middle cerebral arteries (MCA) and penetrating arterioles (PA) were isolated from male Long-Evans rats, mounted in a tissue bath, and pressurized. After the development of spontaneous tone, inside diameters were 186 ± 5 μm ( n = 28) for MCA and 65 ± 3 μm ( n = 37) for PA. MCA and PA constricted ∼20% with increasing flow. Flow-induced constriction persisted in MCA and PA after removal of the endothelium. After removal of the endothelium, the luminal application of a polypeptide containing the Arg-Gly-Asp amino acid sequence (inhibitor of integrin attachment) abolished the flow-induced constriction. Similarly, an antibody specific for the β3-chain of the integrin complex significantly inhibited the flow-induced constriction. The shear stress-induced constriction was accompanied by an increase in vascular smooth muscle Ca2+. For example, a shear stress of 20 dyn/cm2constricted MCA 8% ( n = 5) and increased Ca2+from 209 ± 17 to 262 ± 29 nM ( n = 5). We conclude that isolated cerebral arteries and arterioles from the rat constrict to increased shear stress. Because the endothelium is not necessary for the response, the shear forces must be transmitted across the endothelium, presumably by the cytoskeletal matrix, to elicit constriction. Integrins containing the β3-chain are involved with the shear stress-induced constrictions.

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ROACH, D. C., e A. G. L. HOLLOWAY. "Combined effects of flow curvature and rotation on uniformly sheared turbulence". Journal of Fluid Mechanics 628 (1 giugno 2009): 371–94. http://dx.doi.org/10.1017/s0022112009006296.

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This paper describes an experiment in which a uniformly sheared turbulence was subjected to simultaneous streamwise flow curvature and rotation about the streamwise axis. The distortion of the turbulence is complex but well defined and may serve as a test case for turbulence model development. The uniformly sheared turbulence was developed in a straight wind tunnel and then passed into a curved tunnel section. At the start of the curved section the plane of the mean shear was normal to the plane of curvature so as to create a three-dimensional or ‘out of plane’ curvature configuration. On entering the curved tunnel, the flow developed a streamwise mean vorticity that rotated the mean shear about the tunnel centreline through approximately 70°, so that the shear was nearly in the plane of curvature and oriented so as to have a stabilizing effect on the turbulence. Hot wire measurements of the mean velocity, mean vorticity, mean rate of strain and Reynolds stress anisotropy development along the wind tunnel centreline are reported. The observed effect of the mean shear rotation on the turbulence was to diminish the shear stress in the plane normal to the plane of curvature while generating non-zero values of the shear stress in the plane of curvature. A rotating frame was identified for which the measured mean velocity field took the form of a simple shear flow. The turbulence anisotropy was transformed to this frame to estimate the effects of frame rotation on the structure of sheared turbulence.

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Moore,, James E., Erlend S. Weydahl e Aland Santamarina. "Frequency Dependence of Dynamic Curvature Effects on Flow Through Coronary Arteries". Journal of Biomechanical Engineering 123, n. 2 (1 novembre 2000): 129–33. http://dx.doi.org/10.1115/1.1351806.

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The flow through a curved tube model of a coronary artery was investigated computationally to determine the importance of time-varying curvature on flow patterns that have been associated with the development of atherosclerosis. The entry to the tube was fixed while the radius of curvature varied sinusoidally in time at a frequency of 1 or 5 Hz. Angiographic data from other studies suggest that the radius of curvature waveform contains significant spectral content up to 6 Hz. The overall flow patterns were similar to those observed in stationary curved tubes; velocity profile skewed toward the outer wall, secondary flow patterns, etc. The effects of time-varying curvature on the changes in wall shear rate were expressed by normalizing the wall shear rate amplitude with the shear rate calculated at the static mean radius of curvature. It was found that the wall shear rate varied as much as 94 percent of the mean wall shear rate at the mid wall of curvature for a mean curvature ratio of 0.08 and a 50 percent change in radius of curvature. The effects of 5 Hz deformation were not well predicted by a quasi-static approach. The maximum values of the normalized inner wall shear rate amplitude were found to scale well with a dimensionless parameter equivalent to the product of the mean curvature ratio (δ), normalized change in radius of curvature (ε), and a Womersley parameter (α). This parameter was less successful at predicting the amplitudes elsewhere in the tube, thus additional studies are necessary. The mean wall shear rate was well predicted with a static geometry. These results indicate that dynamic curvature plays an important role in determining the inner wall shear rates in coronary arteries that are subjected to deformation levels of εδα>0.05. The effects were not always predictable with a quasi-static approach. These results provide guidelines for constructing more realistic models of coronary artery flow for atherogenesis research.

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Prakash, Om, O. D. Makinde, S. P. Singh, Nidhi Jain e Devendra Kumar. "Effects of stenoses on non-Newtonian flow of blood in blood vessels". International Journal of Biomathematics 08, n. 01 (gennaio 2015): 1550010. http://dx.doi.org/10.1142/s1793524515500102.

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In this paper, a mathematical model for steady blood flow through blood vessels with uniform cross-section in stenoses arteries has been proposed. Blood is assumed to be non-Newtonian, incompressible and homogeneous fluid. Blood in human artery is represented as Bingham plastic fluid. Expressions for flow rate, wall shear stress, and resistance to flow against stenoses size have been obtained. Obtained results indicate that stenoses size decreases the flow rate and increases the wall shear stress as well as resistance to flow.

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SUBRAMANIAN, G., e DONALD L. KOCH. "Inertial effects on fibre motion in simple shear flow". Journal of Fluid Mechanics 535 (5 luglio 2005): 383–414. http://dx.doi.org/10.1017/s0022112005004829.

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Su, Song-Kai, e Chun-Liang Lai. "Interfacial shear-stress effects on transient capillary wedge flow". Physics of Fluids 16, n. 6 (giugno 2004): 2033–43. http://dx.doi.org/10.1063/1.1714791.

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Amiri, K., M. J. Cervantes e M. Raisee. "Effects of flow unsteadiness on the wall shear stress". IOP Conference Series: Earth and Environmental Science 15, n. 6 (26 novembre 2012): 062033. http://dx.doi.org/10.1088/1755-1315/15/6/062033.

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Tsai, Wu-ting. "Effects of surfactant on free-surface turbulent shear flow". International Communications in Heat and Mass Transfer 23, n. 8 (dicembre 1996): 1087–95. http://dx.doi.org/10.1016/s0735-1933(96)00090-5.

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Rey, A. D. "Analysis of Shear Flow Effects on Liquid Crystalline Textures". Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals 225, n. 1 (febbraio 1993): 313–35. http://dx.doi.org/10.1080/10587259308036237.

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Fülöp, T., Peter J. Catto e P. Helander. "Neutral diffusion and anomalous effects on ion flow shear". Physics of Plasmas 5, n. 9 (settembre 1998): 3398–401. http://dx.doi.org/10.1063/1.873053.

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Dintzis, F. R., e E. B. Bagley. "Shear-thickening and transient flow effects in starch solutions". Journal of Applied Polymer Science 56, n. 5 (2 maggio 1995): 637–40. http://dx.doi.org/10.1002/app.1995.070560513.

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Bove, Lucia, e Maria Rossella Nobile. "Shear flow effects on polymer melts crystallization: kinetics features". Macromolecular Symposia 180, n. 1 (marzo 2002): 169–80. http://dx.doi.org/10.1002/1521-3900(200203)180:1<169::aid-masy169>3.0.co;2-a.

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33

Thompson, R. L., e P. R. Souza Mendes. "AN EXPLICIT CONSTITUTIVE EQUATION FOR PLANE AND AXISYMMETRIC STEADY FLOWS WITH VISCOELASTIC EFFECTS". Revista de Engenharia Térmica 3, n. 2 (31 dicembre 2004): 134. http://dx.doi.org/10.5380/reterm.v3i2.3535.

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Non-Newtonian materials respond differently when submitted to shear or extension. A constitutive equation in which the stress is a function of both the rate of deformation and on the type of the flow is proposed and analyzed theoretically. It combines information obtained in shear, extension and rigid body motion in all regions of complex flow. The analysis has shown how to insert some elastic effects in a constitutive equation that depends only on the present time and position. One advantage of the model is that all the steady rheological functions in simple shear flow and in extensional flow are predicted exactly. Another important property that is included is the split of the extensional viscosity in two parts: one dissipative part that is related to the shear viscosity and an elastic part that is related to the first and second normal stress coefficients in shear. A discussion involving the dimensionless numbers that relate elastic and viscosity effects is also given.

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Blaisdell, G. A., N. N. Mansour e W. C. Reynolds. "Compressibility effects on the growth and structure of homogeneous turbulent shear flow". Journal of Fluid Mechanics 256 (novembre 1993): 443–85. http://dx.doi.org/10.1017/s0022112093002848.

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Compressibility effects within decaying isotropic turbulence and homogeneous turbulent shear flow have been studied using direct numerical simulation. The objective of this work is to increase our understanding of compressible turbulence and to aid the development of turbulence models for compressible flows. The numerical simulations of compressible isotropic turbulence show that compressibility effects are highly dependent on the initial conditions. The shear flow simulations, on the other hand, show that measures of compressibility evolve to become independent of their initial values and are parameterized by the root mean square Mach number. The growth rate of the turbulence in compressible homogeneous shear flow is reduced compared to that in the incompressible case. The reduced growth rate is the result of an increase in the dissipation rate and energy transfer to internal energy by the pressure–dilatation correlation. Examination of the structure of compressible homogeneous shear flow reveals the presence of eddy shocklets, which are important for the increased dissipation rate of compressible turbulence.

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35

Zhao, Hanqing, Jing Yan, Saiyu Yuan, Jiefu Liu e Jinyu Zheng. "Effects of Submerged Vegetation Density on Turbulent Flow Characteristics in an Open Channel". Water 11, n. 10 (16 ottobre 2019): 2154. http://dx.doi.org/10.3390/w11102154.

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The vegetation density λ affects turbulent flow type in the submerged vegetated river. This laboratory study investigates different types of vegetated turbulent flow, especially the flow at 0.04 < λ < 0.1 and λ = 1.44 by setting the experimental λ within a large range. Vertical distributions of turbulent statistics (velocity, shear stress and skewness coefficients), turbulence kinetic generation rate and turbulence spectra in different λ conditions have been presented and compared. Results indicate that for flow at 0.04 < λ < 0.1, the profiles of turbulent statistics manifest characteristics that are similar to those of both the bed-shear flow and the free-shear flow, and the turbulence spectral curves are characterized with some slight humps within the low-frequency range. For λ = 1.44, the turbulent statistics above the vegetation top demonstrate the characteristics of boundary-shear flow. The spectral curves fluctuate intensely within the low-frequency range, and the spectra of low-frequency eddies above vegetation top are significantly larger than the values below. The change of turbulent flow type induced by an increase of λ would increase the maximum value of turbulence kinetic generation rate GS and change the point where GS is vertically maximum upwards to the vegetation top.

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36

Ervin, E. A., e G. Tryggvason. "The Rise of Bubbles in a Vertical Shear Flow". Journal of Fluids Engineering 119, n. 2 (1 giugno 1997): 443–49. http://dx.doi.org/10.1115/1.2819153.

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Full numerical simulations of two- and three-dimensional bubbles in a shear flow, by a finite difference front tracking method, are presented. The effects of inertial, viscous, gravitational, and surface forces on the lift of a deformable bubble rising due to buoyancy in a vertical shear flow, are examined. Bubbles with a large surface tension coefficient migrate toward the downward moving fluid, as predicted analytically for a cylinder or a sphere in a shear flow. Bubbles with smaller surface tension deform, and generally migrate in the opposite direction. The combined effects of the shear flow and the buoyancy deform the bubble in such a way that the circulation around the deformed bubbles is opposite to that of undeformed bubbles.

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37

Ramadan, K., e Iskander Tlili. "Shear work, viscous dissipation and axial conduction effects on microchannel heat transfer with a constant wall temperature". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 230, n. 14 (29 luglio 2015): 2496–507. http://dx.doi.org/10.1177/0954406215598799.

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Convective heat transfer in a microchannel rarefied gas flow with a constant wall temperature boundary condition is investigated numerically. The boundary shear work, viscous dissipation and axial conduction are all included in the study. An analytical solution is also derived for the fully developed flow condition including the boundary shear work. The proper thermal boundary condition considering the sliding friction at the wall is implemented. A comparative study is performed to quantify the effect of the shear work on heat transfer in the entrance – and the fully developed – regions of the microchannel for both gas cooling and heating. The results demonstrate that the effect of shear work on heat transfer is significant and it increases with increasing both the Knudsen number and Brinkman number. Neglecting the shear work in a microchannel slip flow leads to over- or under estimation of the Nusselt number considerably. For a fully developed flow in a microchannel with constant wall temperature boundary condition, the contribution of the shear work to heat transfer can be around 55% in the vicinity of the upper limit of the slip flow regime, regardless of how small the non-zero Brinkman number can be. Including the shear work is therefore crucial in the analysis of microchannel heat transfer and should not be neglected.

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38

Asakawa, Koji, e Takeji Hashimoto. "Shear‐flow effects on self‐assembly of semidilute solutions of off‐critical polymer mixtures: Shear‐hysteresis effects". Journal of Chemical Physics 105, n. 12 (22 settembre 1996): 5216–23. http://dx.doi.org/10.1063/1.472364.

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39

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, n. 7 (28 luglio 2022): e0271469. http://dx.doi.org/10.1371/journal.pone.0271469.

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Abstract (sommario):

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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40

Ouriev, Boris. "Rheology and Rheometry of Aluminum Alloys: Influence of Shear and Vibration on Aluminum Flow Properties". Solid State Phenomena 116-117 (ottobre 2006): 558–64. http://dx.doi.org/10.4028/www.scientific.net/ssp.116-117.558.

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Understanding of flow properties and flow effects of liquid and semisolid aluminum became a key solution for know-how of casting process. Therefore such properties must be characterized a priory to layout of flow process parameters in order to predict structure formation of aluminum in flow. In order to reach target of material characterization it becomes essential to analyze materials under as close to real process conditions as possible. This task was solved by strong modification of commercial rotational rheometer and application of high-resolution temperature control. Besides understanding the flow properties it is essential to find the way of interactive structure control during flow process. Therefore controllable effects were generated and studied with the help of structure related rheological flow properties. For triggering structure formation an influence of mechanical vibration on flow properties of highly concentrated semisolid alloy is explored in this work. For that experimental set-up was designed and adapted to conventional rotational rheometer with precise rheological characterization capability. Priory to fundamental experiments with highly concentrated aluminum suspension a number of calibration tests were performed. Also prediction of wall slippage in shear flow under vibration was evaluated. Analysis of boundary conditions shows that no considerable side effects were present during shear experiment under vibration. The research reveals precise detection of transition temperatures with the help of steady and transient shear viscosity measurement besides selective measurement of full rheological curves within liquid and semisolid state temperature range. Rheological characterization was performed under shear flow conditions with and without presence of orthogonal to flow direction mechanical vibration. It was found that superposition of mechanical vibration and shear flow radically decreases shear viscosity but only in semisolid state. Liquid state rheological properties shows structural behavior but kept insensitive to application of mechanical vibration. For semisolid alloys, comparison between reference shear viscosities at specified shear rates and those measured under vibration shows considerable differences in flow properties. Conversion of concentrated suspension from strongly shear-thinning to almost Newtonian flow behavior is reported here. It is suggested to relate such phenomenon to non-equilibrium between structure formation and disintegration under vibration and hydrodynamic forces of shear flow. Influence of vibration on structure formation was also well observed during measurement of solidification process. Comparison to reference data shows how sensitive structure of concentrated suspension is to vibration in general and especially during solidification phase. The reveled effects and observations provide a solid bases for further fundamental investigations of structure formation regularities in flow of any highly concentrated systems.

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41

Bai, Tao, Qingzhen Yang e Jian Liu. "Numerical Study of the Purge Flow’s Effect on the Loss Mechanism of the Blocking and Shear Effects". Processes 11, n. 1 (26 dicembre 2022): 50. http://dx.doi.org/10.3390/pr11010050.

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Abstract (sommario):

The loss mechanism of shear and upstream blockage caused by the interaction of the purged flow and ingested gas needs to be systematically studied to optimize the flow near the rim. In order to study the causes and influence factors of blocking and shearing effects and quantify their losses reasonably, the three-dimensional unsteady numerical method validated by the experiment data was adopted to study the turbine with three kinds of sealing structures. The block and shear loss are quantified by integrating the dissipation coefficient in the volume where the specific aerodynamic loss occurs. The result indicated that there was a larger radial velocity and smaller tangential velocity of the purged flow relative to the main flow caused the blocking effect. Therefore, its loss is affected by the seal flow and seal structure. The shear effect is mainly affected by the tangential velocity gradient and the axial velocity gradient near the cavity exit. The contribution of the tangential velocity gradient to shear loss is increased with the enlarged sealing efficiency. Through research, it is clear that increasing the purge flow’s tangential velocity is beneficial to reducing the shear loss and has a positive significance for weakening the blocking effect in the main flow channel. Furthermore, the influence of sealing structure on blocking and shear effect must be particularly considered since both are related to sealing efficiency.

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42

Haney, Sean, Baylor Fox-Kemper, Keith Julien e Adrean Webb. "Symmetric and Geostrophic Instabilities in the Wave-Forced Ocean Mixed Layer". Journal of Physical Oceanography 45, n. 12 (dicembre 2015): 3033–56. http://dx.doi.org/10.1175/jpo-d-15-0044.1.

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AbstractHere, the effects of surface waves on submesoscale instabilities are studied through analytical and linear analyses as well as nonlinear large-eddy simulations of the wave-averaged Boussinesq equations. The wave averaging yields a surface-intensified current (Stokes drift) that advects momentum, adds to the total Coriolis force, and induces a Stokes shear force. The Stokes–Coriolis force alters the geostrophically balanced flow by reducing the burden on the Eulerian–Coriolis force to prop up the front, thereby potentially inciting an anti-Stokes Eulerian shear, while maintaining the Lagrangian (Eulerian plus Stokes) shear. Since the Lagrangian shear is maintained, the Charney–Stern–Pedlosky criteria for quasigeostrophic (QG) baroclinic instability are unchanged with the appropriate Lagrangian interpretation of the shear and QG potential vorticity. While the Stokes drift does not directly affect vorticity, the anti-Stokes Eulerian shear contributes to the Ertel potential vorticity (PV). When the Stokes shear and geostrophic shear are aligned (antialigned), the PV is more (less) cyclonic. If the Stokes-modified PV is anticyclonic, the flow is unstable to symmetric instabilities (SI). Stokes drift also weakly impacts SI through the Stokes shear force. When the Stokes and Eulerian shears are the same (opposite) sign, the Stokes shear force does positive (negative) work on the flow associated with SI. Stokes drift also allows SI to extract more potential energy from the front, providing an indirect mechanism for Stokes-induced restratification.

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43

Ahmad, N., E. Fouad e F. Ahmad. "Effect of Shear Flow on Crystallization of Sydiotactic Polypropylene/Clay Composites". Engineering, Technology & Applied Science Research 8, n. 4 (18 agosto 2018): 3108–12. http://dx.doi.org/10.48084/etasr.2079.

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Abstract (sommario):

The high sensitivity of crystallization to shear flow is a subject of great research interest the last several years. A set of syndiotactic polypropylene/clay composite samples were used to examine the effect of shear flow on crystallization kinetics. This phenomenon alters both processing and material final properties. In the present work, the effects of clay contents and shear flow on the rate of flow induced crystallization were investigated using rheological technique. Small amplitude oscillatory shear experiments were performed using advanced rheometric expansion system (ARES). The crystallization rate is found to alter by both shear and clay contents in the polymer composites.

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44

Miyanaga, Norifumi, Mitsumi Nihei e Jun Tomioka. "Effects of Flow Properties of Lithium Soap Greases on Bearing Torque". Key Engineering Materials 823 (settembre 2019): 123–27. http://dx.doi.org/10.4028/www.scientific.net/kem.823.123.

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This study describes the influence of flow properties of lithium soap greases on torque of small ball bearings. Three types of greases with different worked penetration were tested in this study. Their rheological properties are revealed by a cone plate type rheometer. Shear stresses under various shear rates are fitted with the Herschel-Bulkley equation. In addition, viscoelastic behaviors of the greases are measured by small amplitude oscillatory shear. The crossover stress that means the shear stress at G’=G” is obtained for the greases. Then, the bearing torque when three types of greases are used as a lubricant is measured. As the results, the grease with higher crossover stress shows the lower bearing torque regardless of that it has larger apparent viscosity. On the other hand, the grease with lower crossover stress shows the higher bearing torque regardless of that it has lower apparent viscosity. These results imply that the channeling state appears in the grease with higher crossover stress while the churning state appears in the grease with lower crossover stress.

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45

Jeyakumar, Manickaraj, e Sumanth Shankar. "Rheology of Liquid Al, Zn and Zn-7wt%Al Systems". Materials Science Forum 690 (giugno 2011): 226–29. http://dx.doi.org/10.4028/www.scientific.net/msf.690.226.

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Abstract (sommario):

The flow behavior and viscosity of pure aluminum, zinc and Zn-7wt%Al liquids were quantified with the effects of temperature and shear rate by rotational rheometry experiments. These systems exhibited a non-Newtonian, shear thinning and non-thixotropic flow behavior where in the liquid metal viscosity decreases with increasing shear rates. The temperature dependence of viscosity followed the Arrhenius equation. Moreover, at high shear rate regimes the flow resembles a nearly Newtonian behaviour.

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46

Tremblay, Joshua C., Arman S. Grewal e Kyra E. Pyke. "Examining the acute effects of retrograde versus low mean shear rate on flow-mediated dilation". Journal of Applied Physiology 126, n. 5 (1 maggio 2019): 1335–42. http://dx.doi.org/10.1152/japplphysiol.01065.2018.

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Arterial endothelial function is acutely and chronically regulated by blood flow-associated shear stress. An acute intervention employing modest forearm cuff occlusion to simultaneously increase retrograde and decrease mean brachial artery shear rate for 30 min evokes transient impairments in flow-mediated dilation (FMD). However, the independent influence of the low mean versus the retrograde shear stress components is unclear. Healthy young adults [ n = 24 (12 women, 12 men); 22 ± 2 yr, body mass index = 25 ± 2 kg/m2 (mean ± SD)] completed three laboratory visits within 1 wk. Visits consisted of 45 min of supine rest followed by a brachial artery FMD test (duplex ultrasound) before and after a 30-min intervention: control (shear rate unchanged), cuff (mean shear rate decreased, retrograde shear rate increased), or arterial compression (mean shear rate decreased, no increase in retrograde shear rate). The mean shear rate on the compression visit was targeted to match that achieved on the cuff visit. Cuff and compression trials decreased mean shear rate to a similar extent (cuff: 43 ± 22 s−1, compression: 43 ± 21 s−1; P = 0.850) compared with control (65 ± 21 s−1; both P < 0.001), with the retrograde component elevated only in the former (cuff: −83 ± 30 s−1, compression: −7 ± 5 s−1; P < 0.001). FMD decreased by 29 ± 30% ( P < 0.001) after the cuff intervention and 32 ± 24% ( P < 0.001) after the compression trial but was unchanged on the control visit (−0.3 ± 18%; P = 0.754). This was not altered by accounting for the shear rate stimulus. An increased retrograde shear stress does not appear to be obligatory for the transient reduction in FMD achieved after a 30-min exposure to low mean shear stress. These findings provide novel mechanistic insight on the regulation of endothelial function in vivo. NEW & NOTEWORTHY Low mean and retrograde shear stress are considered atherogenic; however, their relative contribution to the acute regulation of endothelial function in humans is unclear. Matched reductions in mean shear stress (30 min), with and without increases in retrograde shear stress, elicited equivalent reductions in flow-mediated dilation in men and women. These findings afford novel insight regarding the shear stress components governing the acute (dys)regulation of conduit artery endothelial function in vivo.

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47

Huang, Yu, Yi’an Wang e Suran Wang. "Effects of Crushing Characteristics on Rheological Characteristics of Particle Systems". Water 14, n. 4 (11 febbraio 2022): 532. http://dx.doi.org/10.3390/w14040532.

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A particle system’s large-deformation shear flow exhibits obvious random characteristics, making accurate modeling of the particle system difficult. Particle systems, which are frequently used in engineering, are prone to breakage, which introduces additional uncertainty into the system. The purpose of this study was to conduct ring-shear experiments on a variety of common engineering materials in order to quantify the effect of the dynamic crushing process of the particle system on the instability of shear flow. Different shear fracture characteristics may result in a change in the volume trend of the system, from dilatancy to shrinkage. While the mean value of the crushable system’s stress ratio does not increase with shear rate, the stress ratio’s fluctuation characteristic parameters are negatively correlated with shear rate. As particles become more easily sheared, the initial value of the stress ratio fluctuation increases. The effect of shear rate on the fluctuation in the system stress ratio is determined indirectly by the degree of system fragmentation. The study of the particle system’s fluctuation characteristics will aid in developing a stochastic dynamic model for the landslide system in the future, allowing for improved prediction and prevention of landslide disasters.

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48

SUGIOKA, KEN-ICHI, e SATORU KOMORI. "Drag and lift forces acting on a spherical gas bubble in homogeneous shear liquid flow". Journal of Fluid Mechanics 629 (15 giugno 2009): 173–93. http://dx.doi.org/10.1017/s002211200900651x.

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Abstract (sommario):

Drag and lift forces acting on a spherical gas bubble in a homogeneous linear shear flow were numerically investigated by means of a three-dimensional direct numerical simulation (DNS) based on a marker and cell (MAC) method. The effects of fluid shear rate and particle Reynolds number on drag and lift forces acting on a spherical gas bubble were compared with those on a spherical inviscid bubble. The results show that the drag force acting on a spherical air bubble in a linear shear flow increases with fluid shear rate of ambient flow. The behaviour of the lift force on a spherical air bubble is quite similar to that on a spherical inviscid bubble, but the effects of fluid shear rate on the lift force acting on an air bubble in the linear shear flow become bigger than that acting on an inviscid bubble in the particle Reynolds number region of 1≤Rep≤300. The lift coefficient on a spherical gas bubble approaches the lift coefficient on a spherical water droplet in the linear shear air-flow with increase in the internal gas viscosity.

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49

Chiu, Jeng-Jiann, e Shu Chien. "Effects of Disturbed Flow on Vascular Endothelium: Pathophysiological Basis and Clinical Perspectives". Physiological Reviews 91, n. 1 (gennaio 2011): 327–87. http://dx.doi.org/10.1152/physrev.00047.2009.

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Abstract (sommario):

Vascular endothelial cells (ECs) are exposed to hemodynamic forces, which modulate EC functions and vascular biology/pathobiology in health and disease. The flow patterns and hemodynamic forces are not uniform in the vascular system. In straight parts of the arterial tree, blood flow is generally laminar and wall shear stress is high and directed; in branches and curvatures, blood flow is disturbed with nonuniform and irregular distribution of low wall shear stress. Sustained laminar flow with high shear stress upregulates expressions of EC genes and proteins that are protective against atherosclerosis, whereas disturbed flow with associated reciprocating, low shear stress generally upregulates the EC genes and proteins that promote atherogenesis. These findings have led to the concept that the disturbed flow pattern in branch points and curvatures causes the preferential localization of atherosclerotic lesions. Disturbed flow also results in postsurgical neointimal hyperplasia and contributes to pathophysiology of clinical conditions such as in-stent restenosis, vein bypass graft failure, and transplant vasculopathy, as well as aortic valve calcification. In the venous system, disturbed flow resulting from reflux, outflow obstruction, and/or stasis leads to venous inflammation and thrombosis, and hence the development of chronic venous diseases. Understanding of the effects of disturbed flow on ECs can provide mechanistic insights into the role of complex flow patterns in pathogenesis of vascular diseases and can help to elucidate the phenotypic and functional differences between quiescent (nonatherogenic/nonthrombogenic) and activated (atherogenic/thrombogenic) ECs. This review summarizes the current knowledge on the role of disturbed flow in EC physiology and pathophysiology, as well as its clinical implications. Such information can contribute to our understanding of the etiology of lesion development in vascular niches with disturbed flow and help to generate new approaches for therapeutic interventions.

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50

Wein, Ondřej. "Slip effects in oscillatory flow of viscoelastic liquids". Collection of Czechoslovak Chemical Communications 50, n. 11 (1985): 2558–69. http://dx.doi.org/10.1135/cccc19852558.

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Abstract (sommario):

Theory has been submitted of measurement of complex viscosity, accounting, appart from the inertia of liquid, and compliance of the instrument measuring the oscillatory shear stress, also for the effect of the slip of liquid on the wall of the measuring cell.

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