Numerical investigation of the hydrodynamic parameters of blood flow through stenotic descending aorta

Abstract

In this study, the blood flow passing through a three-dimensional geometrically realistic stenosis is investigated both experimentally and numerically. Although the blood flow in stenotic arteries has been extensively studied in the past few decades, not much work has been focused on irregularity of stenosis. Thus, a model of an irregular stenotic descending aorta is used in this work. Due to the irregularity of stenosis model, the governing differential equations for continuity and momentum are solved numerically using finite-volume/finite-difference techniques in the generalized body-fitted coordinates. In order to verify the numerical results, the experimental measured pressure drops are compared with the numerical result. In addition, an improved method for nearly orthogonal grid generation is presented in numerical study. The grid generating system is based on the solution of a set of partial differential equations with finite difference discretization. Numerical calculations are performed to examine the effect of 55% (ratio between cross-sectional area at upstream and stenosis) irregular stenosis on the hemodynamic characteristics such as flow separation zone, wall shear stress and pressure drop. The maximum calculated wall shear stress is related to the maximum velocity gradient due to minimum cross-sectional area at the neck of stenosis. In addition, the pressure is shown as an important characteristic that is effecting on the resistance against the flow in the artery. Based on our results, the 55% irregular constriction is considered critical unlike the studies that have believed the reduction, which is greater than 75% become significant.