Flow-Induced Oscillations in Collapsible Vessels

Understanding the behavior of collapsible vessels is critically important due to their prevalence in many biological systems. In veins, airways, and lymphatic vessels, the ability of a vessel to collapse or deform under varying pressure conditions directly influences flow regulation, disease progression, and organ function. Over the past few decades, numerous studies have focused on the dynamics of collapsible tubes under fluid flow using computational approaches. These investigations have provided insights into steady and unsteady flow dynamics in vessels, elastic and viscoelastic wall responses, and dynamic instabilities such as flow limitation, self-excited oscillations, and even chaotic behavior.

Despite these advancements, a major challenge remains in fully understanding the coupling between fluid flow and structural deformation, particularly when flow separation occurs within the collapsible segment. This results in a complex feedback loop between wall motion and pressure gradients.

In this research, we employ a physics-based one-dimensional model that incorporates the effects of wall elasticity, transmural pressure, and flow separation to better understand the physics of flow-induced oscillations in collapsible tubes under varying wall stiffness, transmural pressure, and Reynolds number conditions.