An Insight into Blood Flow and Wall Shear Stress in Abdominal Aortic Aneurysms Coupling Laboratory and CFD Simulations

Abstract

We studied the hemodynamics of abdominal aortic aneurysms (AAAs) by combining laboratory experiments and numerical simulations, with a focus on potential rupture mechanisms. In particular, we investigated the influence of geometrical features—beyond the commonly used maximum diameter—on flow patterns and the wall shear stress (WSS) distribution. Following our previous in vitro study performed utilizing a symmetrical bulge, we extended the analysis to an asymmetrical aneurysm geometry. Experiments and simulations were conducted under steady flow conditions while varying the Reynolds number over a wide range (490 < Re < 3930), to replicate the flow regimes occurring throughout the cardiac cycle. High-resolution, two-dimensional velocity fields were measured in the lab via image analysis and numerically computed using ANSYS Fluent®. These data enabled a detailed characterization of both flow patterns and WSS distributions in healthy aorta and within the aneurysmal region. The good agreement between numerical and experimental results, as well as consistency with the literature, validates the adopted approach and supports its use for future investigations into AAA hemodynamics and rupture risk assessment.