HEMODYNAMICS IN STENOSED ARTERIES — EFFECTS OF STENOSIS SHAPES

Abstract

A numerical analysis has been carried out to investigate the hemodynamic flow through stenosed arteries having mild (S = 25%) to severe (S = 65%) occlusions and under different regimes of flow Reynolds numbers ( Re ) ranging from 50 to 400. Influence of different stenosis shapes (rectangular, trapezoidal, cosine, and Gaussian) on key hemodynamic parameters e.g., recirculation length, wall shear stress (WSS), pressure drop, and irreversible pressure loss coefficient (C I ) are studied. It has been observed that for S = 25%, no flow separation takes place with cosine and Gaussian shaped stenoses for all the Re values considered, while for rectangular or trapezoidal shapes the flow begins to separate at Re = 400. At higher degrees of stenosis, post-stenotic recirculation is noticed for all the shapes considered — the largest recirculation length being observed with the rectangular shape. The peak centerline velocity in the stenosed region is more sensitive to a change in the degree of occlusion for rectangular stenosis than the other shapes. From the study, it is also revealed that the irreversible pressure loss coefficient (C I ) is the maximum for rectangular shaped stenosis, while it is the least for Gaussian shape. It is observed that at high Re regime, C I becomes insensitive to Re values and can be approximated to be a function of the degree of stenosis (S) and the stenosis shape only.