Numerical study of wedge entry in still water and waves using smoothed particle hydrodynamics methods

In the field of ocean engineering, the problem of structure entry into the water is a typical fluid-structure coupling problem. In this process, predicting impact loads and free surface change processes is of great importance for the design of hull structures. In this research work, the accuracy and stability of the numerical model based on the smoothed particle hydrodynamics (SPH) method have been verified by comparing the numerical results and experiments, including the motion of the wedge and the forces exerted on it during its water entry progress. In addition, a numerical wave flume is constructed by using open boundaries to simulate the free slamming of curved wedges with two different cross-sections into the water in hydrostatic and wave conditions, which is to analyze the impact loads and motion characteristics of the wedges during their entry into the water, as well as the free surface evolution law. Compared with the theoretical solutions of regular waves, the numerical simulation indicated that the open boundary condition technique could reproduce the water surface elevation well. In this way, the calculating cost can be improved owing to the technique implemented in the SPH. The numerical results show that the maximum slamming force on the wedge is proportional to the quadratic of the initial velocity in hydrostatic water. Convex and reverse curved wedges reach maximum vertical slamming loads at different immersion depths separately due to the bottom curve difference. The forces exerted on the wedge and the free surface shape around the wedge are greatly affected by the wave phase when the water entry velocity is kept the same.