Multiple Domain Boundary Element Method Applied to Fluid Motions in a Tank with Internal Structure

In this paper, the tank sloshing and the vibration of the internal structure in contact with the water are discussed by extending the Boundary Element Method (BEM). The BEM has been widely used to solve the nonlinear fluid motions in a tank as well as the potential flow past an obstacle. However, when a tank is fitted with the thin internal structure, the basic BEM will give a numerical error due to the thickness of the plate in the evaluation of the pressure acting on the internal structure. Nishino et al. solved this problem by introducing the Thin Plate Boundary Element Method (TPBEM) with some manipulation of the formula.The basic BEM, in this paper, is extended to the Multiple Domain Boundary Element Method (MDBEM) by dividing the whole fluid domain into several sub-domains. The computer program has been developed and applied to the sloshing of two-dimensional (2D) tank with internal structure and also to the vibration of the internal structure in a tank. Some of the computational results are compared with the ones in the published papers. It shows that they agree well each other and the present method is effective.