Numerical simulation of blood flow in arterial stenosis under steady and pulsatile flow conditions

Abstract

Cardiovascular diseases (CVDs) are among the leading causes of death in the world. In this study, an attempt was made to model the flow dynamics of blood in abnormally narrowed artery. Finite volume solver FLUENT was used for the analysis with the aim of understanding the consequences of increasing the degree of stenosis using a two-equation turbulence model. The compliant nature of the artery was neglected, and Newtonian behavior of the blood flow was assumed for the larger arteries. Steady-flow simulations with 75% area reductions were used to establish the validity of the current models by employing the standard and transitional variant of the k  turbulence models. Subsequently, it was found that transitional k  model was suitable for the low Reynolds number internal flows associated with the transition to turbulence, although only a minor departure in terms of the turbulence intensity peak was observed. Unsteady blood flow was introduced by employing a sinusoidal pulsatile waveform at the inlet. The pulsatile nature of the blood flow was investigated in the range of the constriction ratio from 60% to 90%, with an inlet-specified pulse. It was hypothesized that the severity of the stenosis played a major role in the initiation of the turbulence, since no major turbulence was reported for the 60% and 75% area reductions, while increasing the constriction ratio of 90% significantly altered the flow dynamics and triggered the transition to turbulence much earlier than anticipated. The outcome of current numerical efforts was expressed in terms of wall shear stress, a hemodynamically relevant parameter.