The Flow Behavior of a Biofluid in a Separated and Reattached Flow Region

Abstract

The flow behavior of human blood in a separated and reattached flow region is investigated. Hemorheological data that account for the yield stress and shear-thinning non-Newtonian characteristics of blood are used. The governing mass and momentum conservation equations along with the Herschel–Bulkley constitutive equation are solved numerically using a finite-difference scheme. Two inflow velocity profiles are considered, uniform and fully developed (fd) ones. A parametric study is performed to reveal the impact of inflow velocity profile, upstream flow restriction, and rheology on the recirculation strength and reattachment characteristics of the flow field. Uniform inflow conditions result in larger relative recirculation intensity, in comparison with the fd ones, only for a moderate upstream flow restriction. The separated flow region size in the case of a fd inflow is always larger than the one observed for uniform inflow. Larger separated flow regions with stronger flow recirculation, are predicted by the Newtonian (N) model in comparison with the yield shear-thinning (HB) model for all studied inflow and upstream restriction conditions. The separated flow region size displays a stronger dependency on the inflow velocity profile and upstream flow restriction, in comparison with the observed dependency on the used hemorheological model.