Experimental study on wave- and current-induced scour around an anti-deposition permeable breakwater

Abstract

Local scour around structures is a hot topic in ocean engineering research. In this study, a physical model is developed to simulate wave- and current-induced scour around a novel anti-deposition permeable breakwater. The scour process is monitored by applying acoustic Doppler velocimetry (ADV) at 32 points that are uniformly arranged along the front and back sides of the model. The scour topography and scour depth are investigated in detail under various wave and current conditions. The experimental results indicate that the maximum scour depth and scour range increase with increasing wave height and period of the incident wave, water depth, or water velocity. The combined wave–current condition results in a larger scour range and longer equilibrium scour time than the wave- or current-only condition. The results further indicate that the lower board that is set for sediment trapping serves to protect the sediment around the pile, that the maximum equilibrium scour depth is smaller than that without the lower board, and that the scour pit is farther away from the model in the presence of the lower board.