On the Study of Fluid Flow through a Compliant Tube with Internal Obstructions: Coupled Experimental and Numerical Investigation

Flow through flexible tubes with internal blockages is common in biological systems, especially in conditions like atherosclerosis. These blockages can significantly affect blood flow and disease progression, making it important to understand the fluid–structure interaction (FSI) involved. In this study, we combined simulations in COMSOL with lab experiments to examine flow through a soft tube containing a fixed spherical obstruction. The setup used an elastic PDMS tube with pressure sensors at both ends and pulsatile flow from a peristaltic pump. Tube motion was captured with high-speed video and analyzed using custom Python scripts. A matching FSI model in COMSOL reproduced the experimental conditions and material properties. Simulations closely matched the experimental data, including pressure drop, tube deformation, and dynamic behavior. Results showed that the tube's flexibility reduced pressure loss compared to a rigid tube, while the obstruction caused local flow acceleration and pressure hysteresis. These insights improve our understanding of FSI in obstructed flexible vessels and have direct relevance to cardiovascular disease modeling.