Numerical simulation of the spatio-temporal evolution of the flow in the model of abdominal aorta bifurcation with stenosis in the one of the common iliac arteries

Abstract

The structure of the pulsating flow in the model of the average configuration, including the bifurcation of the abdominal aorta and subsequent bifurcation of the iliac arteries with axisymmetric hemodynamically significant stenosis in the right common iliac artery, is researched by numerical method. It has been shown that the presence of stenosis in this artery affects the flow structure both downstream and upstream: reverse-flow zones are formed and transverse flow evolution differs significantly from the structure of the flow in a healthy branch. The stenosis with the spatial curves of the model leads to the formation of a stable single-vortex flow in the external iliac artery most of the cardiac cycle. In the mentioned artery of the healthy branch various unstable patterns of two-vortex structure form during the cycle. In both internal iliac arteries, there is a transitional flow, from a two-vortex to a single-vortex motion, forms during the cycle. The influence of the presence of stenosis on the structure of the transverse flow in the internal iliac artery is insignificant. The most likely regions for atherosclerotic lesions of the vascular wall, characterized by the minimum values of time-averaged wall shear stresses and the maximum values of oscillatory shear index, are the stenosis region and the external wall of the common iliac artery.