Abstract
This paper proposes a non-interface-fitted mesh method for simulating complex fluid-structure interaction (FSI) problems that is consistent with two physical conditions at the FSI interface. The first is the continuity of velocities and surface forces at the interface, and the second is the discontinuity of fluid velocity gradients and pressures over the interface. An extended finite element method (X-FEM) combined with sharp interface enrichment functions is introduced to reproduce the two discontinuities without inconsistent factors resulting from natural usage of non-interface-fitted meshes. Lagrangian Lagrange-multiplier technique is employed to impose the FSI coupling conditions onto the Eulerian fluid and Lagrangian structural meshes. This method enables us to handle general FSI problems being comparable to reliable interface-fitted methods. Fundamental formulations and performance assessment of the proposed method are presented in this paper.
