Physiological Non-Newtonian blood flow through several doubly stenosed arteries

Most. N. Akhter, K. Mamun, M. M.Rahman, M. Ali

Abstract: A numerical analysis of physiological blood flow in a three-dimensional artery with double stenosis has been performed to observe the flow behavior. The vessel wall is considered to be rigid. The degree of stenosis has been varied for the analysis. 65%-65%, 65%-85%, 85%-65% and 85%-85% by area reduction are examined for four doubly stenosed arteries. Physiological and parabolic velocity profiles have been imposed for inlet boundary conditions. The investigation covers a Reynolds number range of 96 to 800. A low Reynolds number model is used in the governing equations. Non-Newtonian constitutive equations of Cross models are used for the simulation. The numerical results are presented in terms of velocity, pressure, wall shear stress (WSS) distributions and cross-sectional velocities as well as the streamlines contours. The maximum wall shear stress is noted in the throat region at peak systole. Throats of 85% reduction of cross sectional area create more change in wall shear stress than the throat of 65% cross-sectional area at any time-phase in all geometries. Pressure distributions demonstrate that in every case, the pressure difference in a 85%-85% stenotic artery is higher than that in the other three stenotic arteries. Velocity increases in the throat regions as a function of the increases in severity of the stenosis. Turbulence is observed downstream of the throats of 85% stenosis in all geometries. The flows in throats of 85% reduction of cross-sectional area in all geometries create a recirculation region downstream of the throat region and the recirculation region increases with an increase of the minimum velocity of inlet flow.

Series on Biomechanics, Vol.31, No.1 (2017), 12-26

Keywords: atherosclerosis; non-Newtonian; Viscoelastic fluid

Date published: 2017-06-19