The surrounding cell method based on the S-FEM for analysis of FSI problems dealing with an immersed solid

In this paper, a numerical method based on the cell-based smoothed finite element method is proposed to analyze three-dimensional fluid-solid interaction problems. Applying the gradient smoothing technique to the fluid and solid domain, the fully-coupled FSI formulation is achieved, and the analysis is performed by means of polyhedral smoothed finite elements. The element shape function based on the linear point interpolation leads to simple element formulation and a good geometric adaptability. Due to the properties of the smoothed finite element method, it is possible to connect non-matching meshes by polyhedral elements and provide seamless connection without overlapping or gap satisfying the interfacial conditions of continuity and force equilibrium, which is verified through the patch test. In addition, a treatment for dealing with moving boundaries in FSI problems with an immersed solid is proposed in the framework of local remeshing. By adopting a surrounding cell around a submerged solid, ill-shaped meshes occurring due to solid motion is reconstructed effectively. The effectiveness of the proposed scheme is illustrated through numerical examples in comparison with some previous works.