Pulsatile CFD Numerical Simulation to investigate the effect of various degree and position of stenosis on carotid artery hemodynamics

This study is intended to investigate the effect of various degree and position (pre-bifurcation and post-bifurcation) of stenosis on carotid artery hemodynamics trough realistic CFD numerical simulations with appropriate turbulence model. The blood rheological properties were assumed as incompressible and Newtonian fluid. A 3 dimensional model of a non-stenotic carotid artery model was used this investigation. Several turbulence model were tested. The non-stenotic artery geometry was altered as 30% and 70%pre-bifurcation stenosis model, 30% and 70% post-bifurcation stenosis model. Pulsatile simulations were conducted for the non-stenotic and each stenotic artery models. The SST k-ω with Low-Reynolds number was found to be more appropriate for the simulation. As the degree of pre-bifurcation stenosis increases from 30% to 70%, the ICA maximum velocity increases from 12% to 65%. Also, the ECA maximum velocity increases from 5% to 45%. Besides, the ICA velocity ratio decreases by 22% but the ECA velocity ratioincreases by 101%. As the degree of post-bifurcation stenosis increases, the ICA maximum velocity takes a longer time to decrease after the peak systole velocity and the ECA maximum velocity becomes higher than a non-stenotic artery throughout the cardiac cycle. A mild stenosis at post-bifurcation does not show much effect on the carotid artery hemodynamics. However, even a mild stenosis at pre-bifurcation resulted in fluctuating maximum velocity at both ICA and ECA, especially during the diastole of the cardiac cycle