Experimental Study of Flow Behavior in Aneurysm with Varying Bottleneck Factor

Aneurysms are irregular enlargement of weakened blood vessels and their rupture can be fatal in some cases. Earlier clinical studies have shown that the morphology of an aneurysm is correlated with the risk of rupture. The objective of this investigation was to study the impact of morphology on flow behavior in an aneurysm sac. Two idealized saccular aneurysm models with different bottle-neck factors were used and an in-house experimental setup was developed to enable inflow conditions such as Womersley number and Reynolds number to be controlled as needed. Particle Image Velocimetry measurements were performed on the mid-vertical planes inside the aneurysm sac. The flow evolution, vortex path, and vortex strength were determined using the velocity field data. Proper Orthogonal Decomposition was used to identify the temporal/spatial behavior of the large-scale structures inside the aneurysm. A low-order velocity field was used to analyze the large-scale structures inside the aneurysm. The results showed that the vortex path was primarily influenced by the change in Womersley number, while the formation of secondary vortices was related to the change in Reynolds number.