Experiment-based numerical simulation of unsteady viscous flow in stenotic collapsible tubes Original Research Article

A numerical method using generalized finite differences is introduced to solve a nonlinear axisymmetric model with a free moving boundary to study unsteady viscous flow in collapsible stenotic tubes simulating blood flow in stenotic carotid arteries. The Navier–Stokes equations are used as the governing equations for the fluid. The tube wall is treated as a free moving boundary whose elastic properties (the tube law) are determined experimentally using a Polyvinyl Alcohol (PVA) hydrogel artery stenosis model. Longitudinal tension is included in the tube law. Physiologically-relevant pressure conditions and parameters are used in the simulation. Our results indicate that severe stenoses cause cyclic pressure changes between positive and negative values at the throat of the stenosis, cyclic tube compression and expansions, and shear stress changing directions in the region just distal to the stenosis under unsteady conditions. These critical mechanical conditions may be related to excessive artery fatigue and possible plaque cap rupture. Computational and experimental results are compared and reasonable agreement is found.