Effects of Severity and Dominance of Viscous Force on Stenosis and Aneurysm during Pulsatile Blood Flow using Computational Modelling

Abstract

Cardiovascular diseases are the predominant cause of the death globally. It has become a challenge for the clinicians to understand the behavior of the stenoses and aneurysms at different stages of the growth. A numerical analysis based on a finite volume approach is employed for a 2-D axisymmetric, incompressible, laminar flow to simulate and compare the pulsatile blood flow in the models of arterial stenosis and aneurysm of the same sizes. Two key parameters, Radial velocity distribution and wall shear stress (WSS) distribution, have been considered for analyzing and comparing stenosis and aneurysm of same sizes of 30% and 50% severity. These parameters have been compared using unsteady blood flow of two frequencies: Womersley number (W0) of 7.75 and 10. In addition, the extent of the effect of Womersley number (W0) has been discussed. A flow input waveform is presented in terms of sinusoid. The results implicate that the Womersley number has a little effect on the flow field when the sizes were varied, which indicates the dominance of viscous force on the flow field of the models considered. It has been observed that the severity of the stenosis or aneurysm has significant effect on the flow field and wall shear stress. It has been concluded that, for a particular depth of stenosis and aneurysm, with the same flow inputs, WSS is significantly high in the stenosis compared to that in aneurysm indicating severe risk in stenosis.