High-Fidelity Simulation of Collapsible Vessels Using a Novel Immersed Boundary Method

The dynamic interactions between the blood flow and collapsible vessels give rise to intricate, non-linear, and fluctuating behaviors, including self-excited oscillations and internal flow instabilities. In this study, high-fidelity simulations using a novel sharp-interface immersed boundary method are employed to study such complex dynamic interactions. Both steady and pulsatile flow conditions are predicted by controlling the internal pressure gradient and transmural pressure. The study finds strong agreement between simulations and experimental data, suggesting vessel deformation follows Shapiro's tube law under steady conditions. Additionally, pulsatile cases show self-oscillation within a critical transmural pressure range. These findings shed light on the mechanisms behind self-excited oscillations and provide valuable insights into the behavior of physiological systems with collapsible vessels subject to pulsatile flow.