A cut-cell finite volume - finite element coupling approach for fluid-structure interaction in compressible flow

TL;DR

This paper introduces a novel coupled finite volume and finite element method for simulating fluid-structure interactions in compressible flows, enabling accurate interface tracking and handling complex deformations.

Contribution

It presents a new loosely coupled approach using cut-cell Immersed Boundary and Mortar methods for improved accuracy in FSI problems with compressible flows.

Findings

Validated with 2D shock-loaded rigid and deformable cases

Studied aeroelastic flutter onset in a thin plate

Demonstrated 3D interaction with a shock wave and a flexible shell

Abstract

We present a loosely coupled approach for the solution of fluid-structure interaction problems between a compressible flow and a deformable structure. The method is based on staggered Dirichlet-Neumann partitioning. The interface motion in the Eulerian frame is accounted for by a conservative cut-cell Immersed Boundary method. The present approach enables sub-cell resolution by considering individual cut-elements within a single fluid cell, which guarantees an accurate representation of the time-varying solid interface. The cut-cell procedure inevitably leads to non-matching interfaces, demanding for a special treatment. A Mortar method is chosen in order to obtain a conservative and consistent load transfer. We validate our method by investigating two-dimensional test cases comprising a shock-loaded rigid cylinder and a deformable panel. Moreover, the aeroelastic instability of a thin plate structure is studied with a focus on the prediction of flutter onset. Finally, we propose a three-dimensional fluid-structure interaction test case of a flexible inflated thin shell interacting with a shock wave involving large and complex structural deformations.