Prediction of vortex structures in pulsatile flow through S-bend arterial geometry with different stenosis levels

Abstract

Arterial stenosis poses a high cardiovascular risk, and clinical intervention is needed when these stenoses grow beyond a specific limit. The study of vortex dynamics in these diseased arteries can be beneficial to understand its severity. Therefore, in the present work, we have investigated the flow structures in an S-bend arterial geometry with different levels of stenosis using a sharp interface immersed boundary method. We have observed an onset of Kelvin-Helmholtz-type vortex roll-up for higher degrees of stenoses. Fluctuations in the wall shear stress are observed for higher stenosis degrees. However, these fluctuations depend on the position and length of the stenosis. Newtonian and non-Newtonian Carreau fluids predict similar vortex structures, although minor differences in the Kelvin-Helmholtz vortex structures and associated fluctuations are observed in the diastolic phase. The Newtonian fluid predicts a slightly longer low time-averaged wall shear stress (≤0.5 Pa) region immediately after the stenosis compared with the Carreau fluid in the 58 % blockage S-bend artery.