Stenosis in arteries of human is a common occurrence and for many years researchers have endeavored to model the flow of blood through stenosed arteries. Arterial stenosis such as Atherosclerosis is one of the most serious forms of arterial diseases which homodynamic factors play a very significant role in the formation and proliferation of it. So this is an important field of study as arterial diseases are a chief cause of death. Stenosis occurs more often in curved artery such as left coronary artery (LCA) that has a mild curvature. In this study a 3-dimensional model of left coronary artery with 40% and 60% cross-sectional area reductions (stenosis) is considered. The main assumptions are laminar, 3-dimensional geometry, incompressible, steady and pulsatile flow. Blood is assumed to have Newtonian and non-Newtonian (with Herschel Bulkley model) behavior.The governing equations, continuity and momentum, are non-dimensionalized with respect to specific variables. The set of governing differential equations are integrated to yield of finite difference equations and then solved together with procedure of the SIMPLE program. Flow features such as velocity profile, wall shear stress (WSS) distributions, f.Re in length of artery and pressure drop in post stenotic region in specific non-dimension time and for all model are presented. According to obtained results the wall shear stress in Newtonian model is more than Non-Newtonian model. In stenosis section and pulsatile flow model this amount varies periodically (variations is very more strong1y) that cause Endothelium cells is damaged. Obtained results agree with previous work in simple cases.
