scholarly journals Studying Disturbance Wave Velocity and Wall Shear Stress of Vertical Upward Annular Flow in Narrow Rectangular Channel

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Antai Liu ◽  
Changqi Yan ◽  
Fuqiang Zhu ◽  
Haifeng Gu ◽  
Suijun Gong
Keyword(s):  
Experimental Data ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Wave Velocity ◽  
Annular Flow ◽  
Rectangular Channel ◽  
Disturbance Wave ◽  
New Correlation ◽  
Current Experimental Data ◽  
Wall Shear

As two important parameters, the velocity of disturbance wave and the wall shear stress in annular flow are very important to solve the closed equations of the mechanical model for annular flow. In this study, the disturbance wave velocity and wall shear stress of annular flow in a vertical narrow rectangular channel with a cross section of 70 mm × 2 mm were studied. According to the experimental results, it is found that the wave velocity and wall shear stress of disturbance wave increase with increasing gas phase velocity and liquid phase velocity. Also, existing correlations for predicting the velocity of disturbance wave were summarized and evaluated using the current experimental data. A new correlation for wall shear stress based on the disturbance wave velocity has been proposed. Compared with the existing correlation for predicting wall shear stress, this new correlation can well predict the current experimental data and MAPE is only 7.32%.

scholarly journals Measurements of wall shear stress and aortic pulse wave velocity in swine with familial hypercholesterolemia

2014 ◽  
Vol 41 (5) ◽  
pp. 1475-1485 ◽  
Author(s):  
Andrew L. Wentland ◽  
Oliver Wieben ◽  
Dhanansayan Shanmuganayagam ◽  
Christian G. Krueger ◽  
Jennifer J. Meudt ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Pulse Wave Velocity ◽  
Familial Hypercholesterolemia ◽  
Wave Velocity ◽  
Pulse Wave ◽  
Aortic Pulse Wave Velocity ◽  
Wall Shear

Predication of wall shear stress of vertical upward co-current adiabatic air-water annular flow in pipes

2020 ◽  
Vol 368 ◽  
pp. 110797
Author(s):  
Peng Ju ◽  
Liang-ming Pan ◽  
Yikuan Yan ◽  
Qingzi Zhu ◽  
Hui He ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Annular Flow ◽  
Wall Shear

Wall Shear Stress in the Helical Annular Flow with Rotating Inner Cylinder

2007 ◽  
Vol 120 ◽  
pp. 261-266
Author(s):  
Young Kyu Hwang ◽  
Nam Sub Woo
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Annular Flow ◽  
Outer Cylinder ◽  
Tangential Velocity ◽  
Skin Friction Coefficient ◽  
Laminar Flows ◽  
Axial Component ◽  
Hydrodynamic Instabilities ◽  
Wall Shear

An experimental and numerical investigation has been performed in order to study the appearance of hydrodynamic instabilities at low bulk axial Reynolds number in the gap between two coaxial cylinders with a diameter ratio of 0.52, 0.8 and 0.9, whose outer cylinder is stationary and the inner one is rotating. Skin friction coefficient and wall shear stress have been measured for fully developed laminar flows of water when the inner cylinder rotates at the speed of 0~600 rpm. The axial component of velocity is directly affected by the radial/tangential velocity field and rotation of the inner cylinder is found to have a strong influence on the axial velocity distribution, ultimately leading to two maximum in the case of high eccentred inner cylinder at high rotational speeds.

Effects of transmural pressure and wall shear stress on LDL accumulation in the arterial wall: a numerical study using a multilayered model

2007 ◽  
Vol 292 (6) ◽  
pp. H3148-H3157 ◽  
Author(s):  
Nanfeng Sun ◽  
Nigel B. Wood ◽  
Alun D. Hughes ◽  
Simon A. M. Thom ◽  
X. Yun Xu
Keyword(s):  
Experimental Data ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Arterial Wall ◽  
Numerical Study ◽  
Transmural Pressure ◽  
Diffusion Reaction ◽  
Model Parameters ◽  
Optimization Approach ◽  
Wall Shear

The accumulation of low-density lipoprotein (LDL) is recognized as one of the main contributors in atherogenesis. Mathematical models have been constructed to simulate mass transport in large arteries and the consequent lipid accumulation in the arterial wall. The objective of this study was to investigate the influences of wall shear stress and transmural pressure on LDL accumulation in the arterial wall by a multilayered, coupled lumen-wall model. The model employs the Navier-Stokes equations and Darcy's Law for fluid dynamics, convection-diffusion-reaction equations for mass balance, and Kedem-Katchalsky equations for interfacial coupling. To determine physiologically realistic model parameters, an optimization approach that searches optimal parameters based on experimental data was developed. Two sets of model parameters corresponding to different transmural pressures were found by the optimization approach using experimental data in the literature. Furthermore, a shear-dependent hydraulic conductivity relation reported previously was adopted. The integrated multilayered model was applied to an axisymmetric stenosis simulating an idealized, mildly stenosed coronary artery. The results show that low wall shear stress leads to focal LDL accumulation by weakening the convective clearance effect of transmural flow, whereas high transmural pressure, associated with hypertension, leads to global elevation of LDL concentration in the arterial wall by facilitating the passage of LDL through wall layers.

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