Effect of Varying Anastomosis Angles for Non-Newtonian Pulsatile Blood Flow through Artery Bypass Graft Models: an LES Study

A computational analysis is performed using the Large Eddy Simulation (LES) method to predict non-Newtonian pulsatile flow of blood into Artery Bypass Graft (ABG) models with varying anastomosis angles. The traditional end-to-side bypass graft models of three distinct anastomosis angles (30°, 45° & 60°) are created on the 75% idealized arterial stenosis to serve the purpose of vascular reconstruction. A pulsatile parabolic inlet boundary condition with the contemplation of spiral component is formulated to model the naturalistic flow in the blood vessel & non-Newtonian Carreau viscosity model is used. The transient study was performed in the ANSYS Fluent 15.0. Initially, the numerical simulation process has been validated with the results of a classic experimental study and Direct Numerical Simulation (DNS) study. The numerical study found that wall shear stress has significant effect on re-blocking while pressure has smaller effect. The artery bypass configuration of 30° anastomosis angle is the most favorable one for the common end-to-side graft design. As a whole, the LES study has provided basic but novel observations of flow projection in the specific artery bypass graft (ABG) models.