NEWTONIAN AND NON-NEWTONIAN BLOOD FLOW AT A 90∘-BIFURCATION OF THE CEREBRAL ARTERY: A COMPARATIVE STUDY OF FLUID VISCOSITY MODELS

Abstract

The majority of numerical simulations assumes blood as a Newtonian fluid due to an underestimation of the effect of non-Newtonian blood behavior on hemodynamics in the cerebral arteries. In the present study, we evaluated the effect of non-Newtonian blood properties on hemodynamics in the idealized 90[Formula: see text]-bifurcation model, using Newtonian and non-Newtonian fluids and different flow rate ratios between the parent artery and its branch. The proposed Local viscosity model was employed for high-precision representation of blood viscosity changes. The highest velocity differences were observed at zones with slow recirculating flow. During the systolic peak the average difference was 17–22%, whereas at the end of diastole the difference increased to 27–60% depending on the flow rate ratio. The main changes in the viscosity distribution were observed distal to the flow separation point, where the non-Newtonian fluid model produced 2.5 times higher viscosity. A presence of such high viscosity region substantially affected the size of the flow recirculation zone. The observed differences showed that non-Newtonian blood behavior had a significant effect on hemodynamic parameters and should be considered in the future studies of blood flow in cerebral arteries.