A comparison of numerical methods for the large–scale modelling of acoustic coupled fluid-structure interactions of double-walled cylindrical shells

This paper presents a comparison of numerical methods used to model large scale acoustic coupled fluidstructure interaction (FSI) problems for single and double-walled cylindrical shells. The finite element method (FEM) is used to model the structure while the fast multipole boundary element method (FMBEM) is used to model the fluid domain and both models are coupled on the shared boundary surface to allow for the FSI, yielding a coupled FEM-FMBEM formulation. At suitably high frequencies the statistical energy analysis (SEA) method may instead be used to model both the complete fluid domain and the structure. The FEMFMBEM and SEA models are compared for two structural configurations. The first involves a single-walled cylindrical shell while the second case involves a double-walled cylindrical shell, where two cylindrical shells of different radii encapsulate an interior body of water. The SEA model is seen to provide substantially faster solution times at high frequencies, while yielding similar results to the FEM-FMBEM model.