Partitioned solution strategies for coupled BEM–FEM acoustic fluid–structure interaction problems. (May 2015) - Rodríguez-Tembleque, Luis
Highlights: Two partitioned FEM–BEM coupling formulations for acoustic FSI problems are proposed. They interconnect fluid and structure using classical (mortar) or localized Lagrange multipliers (LLM). A preconditioned and projected bi-conjugate gradient iterative solver is proposed for the solution. Mortar method is compared with LLM for acoustic FSI applications with non-matching interfaces. In highly nonconforming interface meshes, LLM presents a better accuracy than classical mortar. Abstract: This paper investigates two FEM–BEM coupling formulations for acoustic fluid–structure interaction (FSI) problems, using the Finite Element Method (FEM) to model the structure and the Boundary Element Method (BEM) to represent a linear acoustic fluid. The coupling methods described interconnect fluid and structure using classical or localized Lagrange multipliers, allowing the connection of non-matching interfaces. First coupling technique is the well known mortar method, that uses classical multipliers and is compared with a new formulation of the method of localized Lagrange multipliers (LLM) for FSI applications with non-matching interfaces. The proposed non-overlapping domain decomposition technique uses a classical non-symmetrical acoustic BEM formulation for the fluid, although a symmetric Galerkin BEM formulation could be used as well. A comparison between the localized methodology and the mortar method in highly non conforming interface meshes is presented. Furthermore, the methodology proposes an iterative preconditioned and projected bi-conjugate gradient solver which presents very good scalability properties in the solution of this kind of problems.