Abstract
The salient hemodynamic flow features in a stenosed artery depend not only on the degree of stenosis, but also on its location in the circulatory system and the physiological condition of the body. The nature of pulsatile flow waveform and local Womersley number vary in different regions of the arterial system and at different physiological state, which affects the local hemodynamic wall parameters, for example, the wall shear stress (WSS) and oscillatory shear index (OSI). Herein, we have numerically investigated the effects of different waveforms and Womersley numbers on the flow pattern and hemodynamic parameters in an axisymmetric stenosed arterial geometry with 50% diametral occlusion. Temporal evolution of the streamlines and hemodynamic parameters are investigated, and the time-averaged hemodynamic wall parameters are compared. Presence of the stenosis is found to increase the OSI of the flow even at the far-downstream side of the artery. At larger Womersley numbers, the instantaneous flow field in the stenosed region is found to have a stronger influence on the flow profiles of the previous time levels. The study delineates how an approximation in the assumption of inlet pulsatility profile may lead to significantly different prediction of hemodynamic wall parameters.
Highlights
The investigation of the flow through a stenosed geometry is of interest because of its significance in connection to vascular diseases, like atherosclerosis which perpetrates to heart attack and stroke [1]
Pulsatile blood flow in stenosed artery has been studied to analyze the influence of different flow waveform and Womersley number on the key hemodynamic parameters
(1) The instantaneous streamlines of the physiological flow show a considerable variation throughout the cycle, characterized by the formation of a vortex just downstream of the stenosis zone during the accelerating phase and the vortex elongation and formation of a second corotating vortex during the decelerating phase
Summary
The investigation of the flow through a stenosed geometry is of interest because of its significance in connection to vascular diseases, like atherosclerosis which perpetrates to heart attack and stroke [1]. Johnston et al [26] analyzed the effect of blood rheology in four different human right coronary arteries through a transient study They found that the Newtonian and non-Newtonian blood viscosity models predict only a little variation in the wall shear stress in the arteries though the particle paths are often predicted differently. Irrespective of the degree, the location of the stenosis in the arterial system and the physiological condition of the body may have different implications on the hemodynamic parameters since the waveform and the local Womersley number of the pulsatile flow differ in different sections of the circulatory system. The main objective of the present work is to numerically study the effects of different waveforms and time periods of oscillation on the flow pattern and hemodynamic parameters. Presented here are the obtained pulsatile flow patterns and wall shear stress distributions in stenosed tubes with three typical flow waveforms found in human common carotid arteries. The artery wall is considered to be noncompliant, and the blood is assumed to be Newtonian
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