Optimal design of vertical porous breakwater height and location protecting sloped beaches against solitary waves

Abstract

Abstract

Abstract Vertical porous breakwaters are widely used to actively protect coastal facilities from extreme waves, such as solitary waves. However, the optimal design parameters, particularly porous breakwater height and location relative to the beach toe, remain insufficiently studied. This study aims to investigate the optimal design of vertical porous breakwater height and location based on various conditions using the FLOW-3D HYDRO numerical model, which can simulate porous media and solitary wave propagation. The numerical model is verified through porous dam-breaking and wave run-up cases to ensure its appropriateness. First, 36 numerical scenarios are conducted to examine the influence of crest freeboard on wave dissipation. The results indicate that, within the investigated numerical conditions, a representative optimal crest freeboard is approximately equal to the incoming solitary wave height. Using this representative value, 126 additional simulations are performed to assess structure placement, and the average optimal location is found to be approximately 27.41 times the initial still water depth measured from the beach toe. These optimal values were obtained under specific numerical conditions, including two-dimensional solitary wave scenarios and a limited parameter range, and therefore caution should be exercised when applying them to general engineering design practices.