Effects of Pulsation and Geometry on Post-Stenotic Oscillatory Flow

抄録

Behavior of transient blood flow behind artery stenosis and its relationship with wall shear stress (WSS) has been numerically analyzed using a computational fluid dynamic modeling of unsteady, incompressible flow in a 2D constricted channel. A train of propagating vortex waves was detected downstream the constriction and, it was found that the nature of this vortex wave correspond to a steep, adverse pressure gradient. Investigation of Strouhal number dependence shows that wavelength and total length of the vortex wave are inversely proportional to the Strouhal number, and the strength of both the primary wave and the secondary disturbance flow increase with increasing Strouhal number. Variation in geometry of stenosis indicates that the vortex wave is dramatically reduced to a jet-stream when the stenosed height exceeds a critical value of about 70% unperturbed depth of the channel, but it shows robustness to the changes in length. The time-dependent WSS gives an extreme value almost six times larger at systole compared to that related to the mean flow but a low and oscillating feature with a mean value approximately one tenth at diastole.