Characteristics of Water Surface Variations around 3-Dimensional Permeable Submerged Breakwaters under the Conditions of Salient Formation

摘要

Submerged breakwaters installed under the water surface are a representative coastal structure to prevent coastal erosion,and various types of submerged breakwaters have been proposed and discussed so far.Generally,submerged breakwaters make the complex wave fields due to abrupt change in water depth at the crown of the breakwater.In this study,wave heights and mean water level formed around a breakwater are examined numerically for three-dimensional permeable submerged breakwaters.OLAFOAM,CFD open source code,is applied in the numerical analysis,and the comparisons are made with available experimental results on the permeable upright wall and the impermeable submerged breakwater to verify its applicability to the three-dimensional numerical analysis.Based on the applicability of OLAFOAM numerical code,the wave height and mean water level distribution formed around the permeable submerged breakwaters are investigated under the formation condition of salient.The numerical results show that as the gap width between breakwaters decreases,the wave height in the center of the gap increases,while it decreases behind the gap,and the installing position of the breakwater from the shoreline has little influence on the change of the wave height.Furthermore,it is found that the decrease of the mean water level near the gap between breakwaters increases with decreasing of the gap width.