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

Abstract

Hemodynamics in highly proximal neck of abdominal aortic aneurysm (AAA) was investigated in an idealized case by using computational fluid dynamics (CFD) technique. The steady and pulsatile flow simulations were carried out and compared. The three-dimensional model was constructed using CAD software and boundary conditions were adopted from the literature based on experimental studies. Grid independency study was performed to test the computational mesh used. Blood was considered as incompressible and Newtonian fluid in steady and transient regimes with no-slip and rigid aortic wall. Finite volume method based on ANSYS Fluent was used to solve the CFD governing equations. The results acquired from CFD post-processing for velocity distributions and flow rate during steady and transient (t = 0.25 s and t = 0.55 s) flow states. Furthermore, velocity distributions showed significant differences between the two cases (steady and transient) in the idealized angulated neck AAA model. During the steady state, the flow was concentrated in the middle of aorta while in transient (a systolic phase) the flow was more pronounced and distributed near 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.