Study of wall shear stress in an idealized 90-bifurcation with Newtonian and non-Newtonian fluid models

D. Liepsch, S. Sindeev, A. Balasso, S. Frolov

Abstract: Wall shear stress (WSS) distribution correlates with initiation of cerebral disorders. Newtonian assumption of blood could affect distribution of WSS and overestimate the risk of initiation of a disorder. The aim of this study was to compare quantitatively a WSS distribution for different viscosity models of blood. An idealized 90°- bifurcation model was used for numerical studies. Four different low-rate ratios between main vessel and branch were simulated. Newtonian, Power Law, Bird-Carreau, Casson and Local viscosity models were used to represent rheological properties of blood. The simulations were done using pulsatile flow conditions with a realistic inlet velocity curve. Comparative analysis showed a significant difference between Newtonian and non-Newtonian models. For high WSS values, a Newtonian model overestimates maximum WSS by 17.35% in comparison with the Local viscosity model. The average difference between Newtonian and non-Newtonian models was 21.92%. The results are in agreement with known experimental studies and show the significance of using a non-Newtonian fluid model for numerical studies of distribution of hemodynamic parameters in the cerebral circulation.

Series on Biomechanics, Vol.31, No.1 (2017), 3-11

Keywords: cerebral circulation; computational fluid dynamics; Hemodynamics; viscosity model

Date published: 2017-06-19