An Efficient HOS-SPH-BEM Coupling Method for Wave-Structure Interaction Problems

In this paper, a potential-viscous coupling method based on Xie’s HOS (Boundary Element Method)-SPH (Smoothed Particle Hydrodynamics) coupling method is proposed by introducing the BEM (Boundary Element Method). The domain decomposition model is adopted with the HOS method generating the incident waves, the BEM propagating the radiation and diffraction waves in the far field, and the SPH method used in the near field around the structure for simulating the wave breaking and nonlinear wave-structure interaction. Therefore, the whole coupling method can be divided into two parts: one-way coupling of HOS-SPH (which has been studied in Xie et al.’s paper) and two-way coupling of SPH-BEM. Similar to Xie et al.’s, Grid2Grid is used to connect the HOS and SPH, meanwhile the velocity and pressure transformation between SPH and BEM is achieved by a linear blending scheme. This coupling method combines the advantage of the potential methods in generating and propagating waves quickly and accurately and the SPH method in adopting the strong nonlinear free surface problems. The numerical results of the HOS, SPH, BEM and SPH-BEM coupling methods are validated by calculating regular and irregular waves. The accuracy of the whole coupling method was verified through the interaction between a two-dimensional freak wave and a three-degree of freedom floating body. Compared with experiment data, the HOS-SPH-BEM coupling method can effectively improve computational efficiency and extensively reduce numerical dissipation. It removes the reflected waves in Xie’s HOS-SPH coupling method.