Numerical analysis of bypass model geometrical parameters influence on pulsatile blood flow

Abstract

The present study is focused on the analysis of pulsatile blood flow in complete idealized 3D bypass models in dependence on three main geometrical parameters (stenosis degree, junction angle and diameter ratio). Assuming the blood to be an incompressible Newtonian fluid, the non-linear system of Navier-Stokes equations is integrated in time by a fully implicit second-order accurate fractional-step method. The space discretization is performed with the help of the cell-centred finite volume method formulated for unstructured tetrahedral grids. In order to model a realistic coronary blood flow, a time-dependent flow rate taken from corresponding literature is considered. For the analysis of obtained numerical results, special emphasis is placed on their comparison in the form of velocity isolines at several selected cross-sections during systolic and diastolic phases. The remainder of this paper is devoted to discussion of walls shear stress distribution and its oscillatory character described by the oscillatory shear index with regard to areas prone to development of intimal hyperplasia or to thrombus formation.

Keywords

• Bypass model
• Pulsatile blood flow
• Stenosis degree
• Junction angle
• Diameter ratio
• Fractional-step method
• FVM