Numerical simulation of blood flow in stenotic arteries

Abstract

A computational study of blood flows in stenotic arteries has been conducted in this research. Through the study, a brand new numerical method which is especially suitable to the problem has been developed. The motivation of this study is based on the belief shared by many researchers that hemodynamics play an important role in the formation and development of atherosclerostic stenosis, which is a chronic inflammatory response in the walls of medium or large arteries due to cardiovascular diseases which causes a majority of deaths in developed countries. In order to understand the hemodynamics of stenosis through a computational approach, numerical methods that are capable to simulate the distinct features of this kind of problem, namely, the rheological properties of blood, pulsating nature, stochastic representation and geometrically complicated boundary, had to be developed. A finite difference lattice Boltzmann method (FDLBM) has been chosen as the base for the construction of the numerical scheme. Extensive validating numerical examples with a wide range of application were carried out. Thus the brand new deterministic/stochastic numerical solver has been shown to be a reliable tool for simulating, not only the present problem, but also other similar kinds of flow phenomena. The newly developed numerical method was then employed to simulate blood flows in stenotic arteries. Two important parameters in hemodynamics - pressure drop and wall shear stress - were investigated. Scaling laws in term of Reynolds number were developed for these two parameters so that a convenient scaled quantitative solution could be applied to understand the role played by them. In order to further demonstrate the capability of the scheme as a reliable computational tool for simulating stenotic arterial flows and to provide a more realistic picture for the investigation, more complicated computational models were simulated. The non-Newtonian effect of blood flow was investigated by using the shear thinning Carreau-Yasuda model. The stochastic effects due to an uncertain driven velocity and/or an uncertain viscosity coefficient in Newtonian fluid were examined. Finally, the development of the unsteady vortex structure after a constriction with pulsatile upstream flow was studied.