Numerical investigation on global responses of surface ship subjected to underwater explosion in waves

Transient fluid-structure interaction (FSI) has always been a challenging problem in ship mechanics. Underwater explosion and its highly nonlinear impact on nearby structures are more complicated. In this paper, the global responses of a surface ship subjected to an underwater explosion in waves are numerically investigated considering the nonlinear coupling between the fluid and structure solvers. The fluid field is modeled with the boundary element method (BEM), while the potential decomposition theory is adopted to take the surface waves into account. The global responses of the ship structure are modeled with the mode superposition method. Then a FSI model is established using the mode decomposition method of the acceleration potential to consider the interaction. An underwater explosion experiment is carried out to validate the numerical model, which shows good agreement between the numerical and experimental results. With the presented model, the interactions between a ship and an underwater explosion bubble both in still water and waves are simulated. The dynamics of the ship global responses and the influence of the waves are analyzed which shows noteworthy nonlinearity.