Numerical Prediction of Flow Recirculation Length Zone in an Artery with Double Stenosis at Low and High Reynolds Numbers

Abstract

Arterial stenosis is a disease that is not frequently studied. The incidence is increasing and its impact on quality of life is not often explored. It is prevalent among individuals of 65 years old and older. It affects their physical functioning, overall health and vitality. Their social functioning and emotional well-being are not left out. Arterial stenosis was simulated using ANSYS (Fluent) Computational Fluid Dynamics (CFD) software package for better understanding of blood flow dynamics and to estimate the risk of complication. Blood flow was numerically simulated to predict the recirculation zone length and wall shear stress. An artery with double stenosis was studied and for the purpose of this investigation, stenosis levels of 15/15%, 75/75%, 15/75%, 75/15%, 15/60%, 20/60%, 45/60% 60/60%, and 75/60% in terms of proximal and distal stenosis are studied over the Reynolds number ranging from 150 to 3000. Blood was considered to be a Newtonian fluid flowing as a steady, three-dimensional, incompressible fluid. The velocity flow streamlines, and wall shear stress contours are presented. Results showed when varying both distal and proximal stenosis, as Reynolds number increases, recirculation zone length decreases in lower levels of stenosis between 15/60% and 45/60% while it remains relatively constant for higher levels of stenosis 60/60% and 75/60%. It was also found that when varying both distal and proximal stenosis, as Reynolds number increases, maximum wall shear stress increases gradually at lower levels of stenosis with almost equal values. At higher levels of stenosis, there was rapid increase in maximum wall shear stress as Reynolds number increases.