Investigation of Broken Wave Dissipation Effects of Submerged Shell Dike in Front of Breakwater

In this study, the effects of a submerged shell dike in front of a breakwater on dissipating broken waves were studied. The dissipation effects of different broken wave heights and the submerged shell dike were investigated through numerical simulations. High-precision wave gauges and pressure sensors were used to collect data. Numerical simulations were performed using OpenFOAM software, based on the Volume of Fluid (VOF) method, to simulate broken waves. The time-histories of broken wave heights simulated by the numerical model were validated by physical experiment results, and the proportion of errors was less than 5.6%. The results show that the broken wave exerted on different positions of the breakwater shows a different time-history of pressures, and the peak pressure decreases with the decreasing broken wave height (from 0.342 to 0.227 m in the model) and increasing radii of the submerged shell dike (from 0.03 m to 0.18 m in the model). Through dimensional analysis, the relationship between the broken wave pressures and the dimensionless parameters related to broken wave height, breakwater height, and the radii of the submerged shell dike were established. Following the attenuation of the broken wave by the submerged shell dike, the equations for estimating broken wave pressures on various points along the breakwater were proposed. These equations are functions of the broken wave height, the radius of the submerged shell dike, and the height of the breakwater.