A new coupling strategy for fluid-solid interaction problems by using the interface element method

This paper presents a new approach to simulate fluid-solid interaction (FSI) problems involving non-matching meshes. The coupling between the fluid and solid domains with dissimilar finite element meshes consisting of 4-node quadrilateral elements is achieved by using the interface element method. Continuity and compatibility conditions across the interface between fluid and solid meshes are satisfied exactly by introducing the interface elements defined on an interfacing region. Importantly, a consistent transfer of loads through the interface elements guarantees the present method to be an efficient approach of the solution strategy to FSI problems. An arbitrary Lagrangian-Eulerian description is adopted for the fluid domain, while for the solid domain an updated Lagrangian formulation is considered to accommodate finite deformations of an elastic structure. The fluid equations for velocity and pressure and the solid equations for velocity are strongly coupled in a single computational domain by means of the interface elements. Numerical results are presented for FSI problems involving non-matching meshes to demonstrate the effectiveness of the methodology.