BEHAVIOR OF WALL SHEAR STRESS NEAR CAROTID ARTERY BIFURCATION AT ELEVATED PULSE RATES

This paper reports a numerical investigation on the blood flow patterns and wall shear stress (WSS) distribution for both healthy and stenosed carotid arteries near the bifurcation region. Pulsatile inflow velocity profiles are considered which resemble the physiological flow waveforms. Outlet pressure variation is specified through a two-element Windkessel model. The Carreau model is used for the non-Newtonian blood rheology. Axial velocity contours and streamtraces are depicted at different phases of the pulsation cycle. Three different pulse rates are considered and the effects of the elevated pulse rates in the spatial distribution of time-averaged WSS and oscillatory shear index (OSI) are reported. It is observed that at the higher pulse rates, the healthy arteries exhibit higher WSS and lower OSI levels while the stenosed arteries behave oppositely. Local velocity fluctuations are identified through frequency analysis of velocity at the post-stenotic region. These fluctuations are observed to be correlated with the low and oscillatory nature of wall shear stress in the stenosed arteries at elevated pulse rates.