Numerical Study on Unsteady Flow Field of Arterial Stenosis

A numerical study has been carried out to analyze the unsteady flow field of a stenotic artery. The artery has 75% stenosis severity with axisymmetric cosine shaped stenosis. The wall of the vessel is considered to be rigid. A sinusoidal pulsatile flow is assumed as inlet boundary condition. The time period of the inlet pulsatile flow is varied as 5, 10, 15 and 20 seconds. A recirculation region is visible at the post stenotic region for all cases and the recirculation region increases at minimum velocity of the inlet flow. The positive peak wall shear stress (WSS) is found to be located proximal to the stenosis throat and negative peak wall shear stress is visible in the post stenotic region for all cases. The variation in time period of inlet flow has no significant effect in the neighbourhood of the stenosis throat but has some variations in the post stenotic region. The peak value of positive WSS is same for all cases but the peak value of negative WSS changes and its location tends to move towards the stenosis throat as the time period of the inlet flow cycle is decreased. For all cases the pressure distributions across and near the stenosis throat are same at maximum inlet flow condition. At accelerating inlet flow condition the pressure distribution shifts towards downward direction for smaller time periods of the inlet flow cycle. The pressure drop across the stenosis throat is same for all cases.