The numerical investigation of regular waves interacting with a submerged horizontal twin-plate breakwater is pre- sented in this paper. A numerical model with an absorbing wave-maker is established based on the VOF method. The validity of the model is verified by experimental results. Comparisons between the numerical and experimental results show that beth the water surface profiles and the wave-induced pressures can be modeled accurately. Wave deformation over the breakwater, water particle velocities around the breakwater, and the wave-induced pressures on the structure are nu- merically investigated. Tile pressure amplitudes of the fundamental and second harmonies on the model surface are exanl- ined in various water depths. The computed and experimental results have revealed that the higher frequency components are generated at the onshore side of the breakwater. Furthermore, the computed results demonstrate a circulating flow formed at the onshore side of the breakwater.
The wave transmission characteristics and wave induced pressures on twin plate breakwater are investigated experimentally in regular and random waves. A total of twenty pressure transducers are fixed on four surfaces of twin plate to measure the wave induced dynamic pressures. The spatial distribution of dynamic wave pressure is given along the surface of the twin plate. The uplift wave force obtained by integrating the hydrodynamic pressure along the structure is presented. Discussed are the influence of different incident wave parameters including the relative plate width B/L, relative wave height Hi / a and relative submergence depth s / a on the non-dimensional dynamic wave pressures and total wave forces. From the investigation, it is found that the optimum transmission coefficient, Kt occurs around B/L = 0.41 - 0.43, and the twin plate breakwater is more effective in different water depths. The maximum of pressure ratio decreases from 1.8 to 1.1 when the relative submergence depth of top plate is increased from -0.8 to ＋0.8.
