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Showing 1 to 19 of 19 for “"Wall shear stresses"”.
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Flow characteristics and wall shear stresses in bifurcated peripheral arteries
… it affects the velocity, blood pressure, shear stresses and flow rates of blood. Femoral artery flow is modeled with blockage at different bifurcation angles (30°,45° and 60°) and it is analyzed at different conditions. A review of stents shows that there are several limitations associated …
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Shear stresses in turbulent flow through concentric annuli
… approach to the direct measurement of wall shear stresses in fully developed turbulent flow in concentric annuli is presented. By means of a specially constructed 6 m test rig known as the 'floating sleeve', results of individual wall shear stresses, friction factors and shear stress …
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Mikroelektrochemische Quantifizierung von Strömungsintensitäten zum Studium der Wirksamkeit von wandreibungsvermindernden Additiven
… transfer intensity of flowing liquid with solid walls determines the flow resistance (wall friction), heat tranfer, mass transfer, and also the likelihood of erosion corrosion initiation on solid surfaces, and is generally characterized in terms of wall shear stresses as an integral parameter. By …
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Struktur-Wirkungsbeziehungen bei der Verminderung der Wandreibung in Strömungssystemen durch supramolekulare Strukturen
… intensities are generally expressed in terms of wall shear stresses as a value for the friction between turbulent flowing liquids and the wall. High molecular polymers and surface active compounds can influence a turbulent flow by reducing the wall shear stress to values which are uncritical for …
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Simulation of blood flows in a stenosed and bifurcating artery using finite volume methods and OpenFOAM
… blockage increases, correspondingly increase the wall shear stresses. High wall shear stresses significantly increase the possibility of rupture of the stenosis/blockage. This can lead to catastrophic consequences in the usual case where the stenosis is caused by tumor growth.
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Numerical simulations of blood flow in arteries using fluid-structure interactions
… simulations were performed assuming the arterial walls are rigid, and then they were extended to deformable arteries where contraction and expansion of the arteries are considered. Moreover, this study also investigated the outcome of bypass surgeries involving end-to-side and end-to-end bypass …
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Numerical modelling of the Oldroyd-B fluid
… a viscoelastic fluid on the flow profile and wall shear stresses are investigated. The results from this work show that using a viscoelastic fluid, rather than a Newtonian fluid, provides additional details regarding the wall shear stress in the arteriovenous fistula.
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Mean Flow and Turbulence Characteristics of Pool -Riffle Structures in Low -Gradient Streams
… and divergence, secondary circulation, wall shear stresses and turbulence, specific of each configuration. Implications for sediment transport, bed and bank morphology and aquatic habitat are discussed. Some of the results presented in this work have been used as a guide for the design, …
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Development of a static bioactive stent prototype and dynamic aneurysm-on-a-chip(TM) model for the treatment of aneurysms
… of blood that collect outside blood vessel walls forming dilatations and leaving arterial walls very prone to rupture. Current treatments include: (1) clipping, and (2) coil embolization, including stent-assisted coiling. While these procedures can be effective, it would be advantageous to …
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A Study of Aspects of the Coupling of Flow and Sediment Transport for Sand and Gravel Dunes
… geometry. 2) An attempt was made to predict bed shear stress over the dunes. Fits were used to extend viscous stresses calculated by a RANS numerical model below the bed surface to the theoretical wall. Shear stresses calculated in this way exhibited significantly different patterns under …
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A Novel Multiblock Immersed Boundary Method Enabling High Order Large Eddy Simulation Of Pathological And Medical Device Hemodynamics
… turbulence kinetic energy levels, viscous wall shear stresses and turbulence energy spectra are used to compare the similarities and differences between the blood flow patterns obtained. Presence of well developed turbulence is detected in the case of TAA whereas TASG showed periodic vortex …
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Hemodynamic analysis of flow near cerebral aneurysms: Insight into aneurysm formation and effects of intervention
… and it is shown that low and oscillatory shear could lead to aneurysm initiation. The second part consists of hemodynamic analysis inside the aneurysm. It is shown that stable flow patterns exist inside the aneurysm with distinct influx and efflux zones that remain unchanged during the …
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Amplitude modulation of velocity and wall shear stress in turbulent channel flow with hemispherical roughness
"Near-wall turbulence cycles tend to be self-sustained in low Reynolds number wall-bounded turbulent flows. However, large-scale structures that reside in the outer region of the flow grow more energetic as Reynolds number increases and impart strong ""footprints"" on the near-wall turbulence. In …
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Shear Stress-Mediated Tumor-Endothelial Cross Talk Regulates the Angiogenic Potential of Breast Tumors In Vitro
… interstitial fluid pressure and aberrant flow shear stress within the tumor microenvironment. While research has shown that the hydrodynamics of the tumor vasculature reduce transport and uptake of therapeutic agents, the underlying mechanisms by which fluid forces regulate vascular …
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Development of a MEMS Sensor for sub-kPa Shear Stress Measurements
… of MEMS sensors for measuring sub-kPa (<1000Pa) wall shear stresses in high-speed turbulent flows. Wall shear stress is an important flow quantity that is used to characterize flows that can be found in aerospace, automotive, and biomedical applications. Sensors that can measure this quantity …
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Laminar and Transitional Flow disturbances in Diseased and Stented Arteries
… that the emergence of abnormal fluid mechanical stresses which dictate the cell mechanotransduction mechanisms and lead to disease progression is dependent on the geometry and compliance of arteries, and pulsatility of blood flow. Understanding of such hemodynamic regulation in relation to …
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Development of an Experimental and Computational Pipeline for Characterizing the Mechanical Properties and Micromechanical Environment within In Vitro 3D Printed Bone Tissue Engineered Scaffolds
… model. The CFD model was used to calculate wall shear stresses (WSS) for various inlet velocities (0.05, 0.10, 0.15, 0.20, and 0.25 mm/s), with 0.15 mm/s producing WSS best within the range of extracellular matrix formation. DMA, DCE-MRI, and CFD all confirmed mechanical characteristics of …
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3-DIMENSIONAL NUMERICAL AND EXPERIMENTAL STUDIES TO MODEL ARTIFICIAL HEART VALVES HEMODYNAMICS
… such as stagnation, recirculation zones and shear stresses. In this research, we established a numerical model using arbitrary Lagrangian Eulerien to study the hemodynamic performance of a bileaflet mechanical heart valve. The 3-dimensional numerical simulation was performed using OpenFOAM, …