Rheological effects on pulsatile hemodynamics in a stenosed tube
The authors investigate the effect of Womersley number \(Wo\) variation for the input pulse on the transient laminar axisymmetric flow through a tube with a small local occlusion. Three rheological models (Newtonian, power-law and Anemada) of human blood are examined using an experimentally validated control volume method. The results show similar structures of the flow field for all the three models. However, the differences in the interaction between inertial viscous forces have a measurable effect on the wall hemodynamic parameters (i.e. time-averaged wall shear stress, spatial wall shear stress gradient and oscillatory shear index). The primary application is pulsatile flow in axisymmetric stenosed artery segments. The results show that for the highest Womersley numbers considered \((Wo=5-12)\), a second corotating vortex is formed distal to the primary vortex. The shear-thinning rheological models exhibit a secondary effect on the flow field which causes subtle changes in the hemodynamic wall parameters. The entrainment of fluid-like particles in the post-stenotic region is considerably affected by the non-Newtonian models. For all rheologies and Womersley numbers considered, the ratio of transient to steady particle residence time is found to be less than or equal to unity for the majority of fluid elements.
scientific article; zbMATH DE number 1452891