Numerical analysis of the three-dimensional model of pulsatile and non-Newtonian blood flow in a carotid artery with local occlusion

The analysis of blood flow in blood vessels, particularly in arteries, is a topic with important clinical applications. The blood can undergo a reduction in its viscosity under shear stress, which is called shear thinning. In this study, the effect of the shear thinning of blood is simulated using the Carreau-Yasuda model, neglecting the viscoelastic effects. The purpose of this investigation is to analyze the pulsatile blood flow in a three-dimensional model of the carotid artery and the effects of occlusion using Ansys Fluent. The results obtained in this study show that, compared to Newtonian fluids, non-Newtonian fluids exhibit significant differences in secondary flow patterns and shear flow behavior. Additionally, the axial velocity in the non-planar branch decreases with obstruction. The maximum shear stress of the walls with Newtonian fluid viscosity exhibits a significant error, and the values are lower than those of walls with non-Newtonian viscosity in most cases. In continuation of this research, vessel occlusion models with different occlusion sizes are analyzed. In the case where the outlet of the vessel is narrowed, an increase in velocity is observed in the furcation area. Although the software cannot simulate rupture, occlusion of the vessel at 80\% and 50\% of the internal diameter is analyzed.