Numerical investigation of the effects of stenosis on hemodynamics in the idealized left coronary artery

In this thesis, the left anterior descending artery is kept constant in the idealized left coronary artery and the angles with the left circumflex artery are determined to be 30º, 75º and 120º. Numerical analyses are performed for the healthy case without stenosis and for the diseased arteries obtained by applying diameter-over-diameter contraction to each vessel. In stenotic arteries, the degree of stenoses vary from 20% to 80% and they are pinpointed on the left main artery, left anterior descending and left circumflex. In this thesis, all numerical analyses are performed with ANSYS Fluent 2021R2 program. In the analysis, the blood is considered as a Non-Newtonian fluid and Carreau model, which assumes that the fluid has non-Newtonian and incompressible features, is used to describe the viscosity of blood. As an inlet boundary condition, mean inlet velocity of the cardiac cycle is applied at the inlet and 80 mmHg pressure condition is applied at the outlets. As a result of the studies, when the WSS values occurring in the stenoses on the arteries are compared considering the angles and the minimum and maximum points of the cardiac cycle, after the degree of stenosis on the LM exceeds 50%, the high WSS areas occurring in the carina region due to insufficient blood delivery begin to disappear. It is observed that the residence time of particles close to the arterial wall occurs around the stenosis, in the areas where flow separation occurs and in the bifurcation zone, and that these areas are prone to plaque formation.