Numerical Investigation of Nonlinear Wave Scattering by a Horizontal Submerged Plate

Submerged plates are widely used as breakwater device and wave energy convertor in costal and ocean engineering. It is of practical importance to account for the effects of plate on wave transformation and nonlinear wave loads on the plate. In this paper, a 2D fully nonlinear numerical wave flume is developed to investigate the nonlinear interactions between a regular wave and a submerged horizontal plate by use of a higher-order boundary element method (HOBEM) based on potential theory. An acceleration potential method is adopted to calculate the transient wave loads on the plate. The proposed model is verified against the published experimental and numerical data for nonlinear wave scattering by a submerged plate. Then numerical tests are performed to investigate the high free harmonics induced by the submerged plate and nonlinear wave loads on it. The second-order analysis shows a resonant behavior which is related to the ratio of the plate length to the second beat length. The wave-load analysis shows that the pressure on the upper surface oscillates more frequently than that on the lower surface.