Advantageous swirling flow in 45 degrees end-to-side anastomosis

Abstract

The effects of swirling flow on the flow field in 45 degrees end-to-side anastomosis are experimentally investigated using a particle image velocimetry technique to reveal fluid dynamic advantages of swirling flow in the vascular graft. Non-swirling Poiseuille inlet flow unnecessarily induces pathological hemodynamic features, such as high wall shear stress (WSS) at the 'bed' side and large flow separation at the 'toe' side. The introduction of swirling flow is found to equalize the asymmetric WSS distribution and reduces the peak magnitude of WSS. In particular, the intermediate swirling intensity of S = 0.45 induces the most uniform axial velocity and WSS distributions compared with weaker or stronger swirling flows, which addresses the importance of proper selection of swirling intensity in the vascular graft to obtain optimum flow fields at the host vessel. In addition, swirling flow reduces the size of flow separation because it disturbs the formation of Dean-type vortices in secondary flow and inhibits secondary flow collision. The beneficial fluid dynamic features of swirling flow obtained in this study are helpful for designing better vascular graft suppressing pathological hemodynamic features in the recipient host vessel.