عنوان مقاله [English]
Arterial occlusion has been one of the most common death causes in the developed and developing societies in the last half-century, and the main reason for the spread of this disease is the unhealthy lifestyle of the majority of people. In the present study, numerical simulation of the steady blood flow through the carotid artery with hypothetical geometry and considering mild (20%), moderate (50%), and severe (80%) occlusion was performed. Furthermore, concentric and eccentric geometries were considered for the stenosis. The shear-thinning behavior of the blood fluid is incorporated by the Carreau–Yasuda model, and the viscoplasticity of blood was ignored. By comparing the non-Newtonian and Newtonian viscosity results, significant differences were found in the secondary flow lines. Shear-thinning behavior affects the secondary flow lines so that the vortices are either not formed or are smaller in size in the middle of the stenosis and subsequent sections. In estimating the maximum wall shear stress, the Newtonian model had a significant error compared to the non-Newtonian one, and the estimated values by the Newtonian model were less than the non-Newtonian in most cases (up to 37% for an 80% stenosis). Finally, the study of axial velocity profiles in the non-planar branch showed that variation of velocity and shear rate caused by stenosis reveals the importance of the non-Newtonian model in calculating streamlines and velocity magnitudes.