Validation of Abdominal Aortic Aneurysm Dynamics: A Comparative Analysis of PIV, CFD, and FSI

Abstract

Flow visualization techniques provide the opportunity to observe the fluid dynamics phenomena that occur in vascular geometries under specific, known conditions. These conditions can then be used to calibrate computational models of identical geometries, a validation that is useful in the assessment of prospective interventions and perturbations. The present study investigated the flow dynamics within both a rigid abdominal aortic aneurysm (AAA) model with an iliac bifurcation and a compliant replica. Velocity fields were experimentally measured in vitro using particle image velocimetry (PIV) and compared with transient CFD and FSI analyses. The results show that the CFD approach is able to predict the patterns of flow from the PIV experiments, which arise from the geometry of the AAA. The FSI representation of the compliant wall PIV experiments showed that the in-plane dynamics visualized by PIV matched by FSI in a qualitative manner. Wall deformation, assessed by means of diameter changes in the cardiac cycle at the midsection of the compliant AAA model, was matched by the FSI analysis with a maximum relative difference of 8%.