Analysis of a 3D Nonlinear, Moving Boundary Problem describing Fluid-Mesh-Shell Interaction

TL;DR

This paper develops a mathematical framework to analyze a complex fluid-structure interaction involving a viscous fluid and an elastic shell supported by a mesh of rods, with applications in biomedical engineering.

Contribution

It proves the existence of weak solutions for a nonlinear moving boundary problem coupling Navier-Stokes equations with elastic shell and rod systems.

Findings

Existence of weak solutions established for the coupled system.

Extension of compactness results to moving domain problems.

Application relevance to blood flow and vascular stents.

Abstract

We consider a nonlinear, moving boundary, fluid-structure interaction problem between a time dependent incompressible, viscous fluid flow, and an elastic structure composed of a cylindrical shell supported by a mesh of elastic rods. The fluid flow is modeled by the time-dependent Navier-Stokes equations in a three-dimensional cylindrical domain, while the lateral wall of the cylinder is modeled by the two-dimensional linearly elastic Koiter shell equations coupled to a one-dimensional system of conservation laws defined on a graph domain, describing a mesh of curved rods. The mesh supported shell allows displacements in all three spatial directions. Two-way coupling based on kinematic and dynamic coupling conditions is assumed between the fluid and composite structure, and between the mesh of curved rods and Koiter shell. Problems of this type arise in many applications, including blood flow through arteries treated with vascular prostheses called stents. We prove the existence of a weak solution to this nonlinear, moving-boundary problem by using the time discretization via Lie operator splitting method combined with an Arbitrary Lagrangian-Eulerian approach, and a non-trivial extension of the Aubin-Lions-Simon compactness result to problems on moving domains.