An Investigation of Pulsatile Blood Flow in an Angulated Neck of Abdominal Aortic Aneurysm using Computational Fluid Dynamics

Abstract

Hemodynamicsin highly proximal neck of abdominal aortic aneurysm(AAA) was investigated in an idealized case by using computational fluid dynamics(CFD) technique. The steady and pulsatileflow simulations were carried out and compared. The three-dimensional model was constructed using CAD software and boundary conditions were adoptedfrom the literature based on experimental studies. Grid independency study was performed totest the computational meshused.Blood was considered as incompressible and Newtonian fluid in steady and transient regimeswith no-slip and rigid aortic wall. Finitevolume method based on ANSYS Fluent was used to solve the CFD governing equations. The results acquired from CFD post-processing for velocity distributionsand flow rate during steady and transient (t = 0.25 sand t = 0.55 s) flow states. Furthermore, velocity distributionsshowedsignificant differences between the two cases(steady and transient) in the idealized angulated neck AAA model. During the steadystate, the flow was concentrated in the middle of aorta while in transient (a systolic phase) the flow was more pronounced and distributednear the wall and tortuous areas more than in a diastolic phase. Flow rate at iliac artery outlets showed different values in both states and slight variance in the right and left iliac arteries. The steady and pulsatile flow comparison using CFD were crucial to understand and investigate the hemodynamic in angulated neck of abdominal aortic aneurysm model.