Investigation on the unsteady hydrodynamic loads of ship passing by bridge piers by a 3-D boundary element method

A 3-D Rankine type Green function boundary element method is developed to estimate the unsteady hydrodynamic interaction during ship passing piers process. To address this moving boundary problem, a free surface re-meshing algorithm based on the combination of local mesh and global mesh is proposed to update fluid boundary and the boundary value formula is solved at each time step. Two alternative numerical models for ship passing piers problem are compared with the current analysis method. Based on the three numerical models, the characteristics of the hydrodynamic loads acting on the passing ship are specified and the critical positions for the peak values have been identified. Simulation results demonstrate that the fluid disturbance induced by the piers is of importance. Therefore, the study of ship–piers hydrodynamic interaction in a river must be handled as a different forward speeds problem. Additionally, the wave elevation effect can only be neglected on condition that the forward speed is very low.