Modeling Blood Pulsatile Turbulent Flow in Stenotic Coronary Arteries

Abstract

Atherosclerosis is a potentially serious illness where arteries become clogged with fatty substances called plaques. Over the years, this pathological condition has been deeply studied and computational fluid dynamics has played an important role in investigating the blood flow behavior. Commonly, the blood flow is assumed to be laminar and a Newtonian fluid. However, under a stenotic condition, the blood behaves as a non-Newtonian fluid and the pulsatile blood flow through coronary arteries could result in a transition from laminar to turbulent flow condition. The present study aims to analyze and compare numerically the blood flow behavior, applying the k-ω SST model and a laminar assumption. The effects of Newtonian and non-Newtonian (Carreau) models were also studied. In addition, the effect of the stenosis degree on velocity fields and wall shear stress based descriptors were evaluated. According to the results, the turbulent model is shown to give a better overall representation of pulsatile flow in stenotic arteries. Regarding, the effect of non-Newtonian modeling, it was found to be more significant in wall shear stress measurements than in velocity profiles. In addition, the appearance of recirculation zones in the 50% stenotic model was observed during systole, and a low TAWSS and high OSI were detected downstream of the stenosis which, in turn, are risk factors for plaque formation. Finally, the turbulence intensity measurements allowed to distinguish regions of recirculating and disturbed flow.