Numerical Simulation of Blood Flow in Aortoiliac Bifurcation with Increasing Degree of Stenosis

The worldwide lethal prevalence of atherosclerotic diseases has made it a crucial topic of research, the descending aorta is a major artery with complex geometry involving curvature, branches, and bifurcation leading to common iliac arteries. This paper aims to scrutinize the intricate blood flow patterns and the flow parameters with the increasing degree of stenosis in the infrarenal aorta, which has been accomplished through computational fluid dynamics modeling. A 3D CAD model of the healthy aortoiliac bifurcation was constructed from MR images, and three diseased models with 32%, 47%, and 71% occlusion in the infrarenal aorta region were constructed. At the inlet, pulsatile velocity and at the outlet pressure boundary conditions were applied, blood was considered Newtonian and turbulence was modeled using Large Eddy Simulation (LES). The numerical simulation was carried out using finite volume method on ANSYS. The predicted hemodynamic parameters like velocity, wall shear stress (WSS), oscillating shear index (OSI), Q-Criterion and turbulence intensity were post-processed for all the models, the analysis of which provides an insight into the myriad processes involved in the inception and evolution of atherosclerosis. The transition of blood flow from laminar to turbulent with increase in the degree of stenosis is a very eminent feature of this study, turbulence is identified in cases with 47%, and 71% occlusion and is dominant in the latter.