Rip current reduction at the open inlet between double submerged breakwaters by installing a drainage channel

Abstract In this study, we performed two-dimensional hydraulic experiments to analyze the hydrodynamic characteristics of wave height, surface elevation, and flow around single submerged breakwater with a drainage channel under regular waves corresponding to storm and normal conditions. On the basis of the two-dimensional experimental results, we also performed three-dimensional numerical simulations to specifically analyze hydrodynamic characteristics around double submerged breakwaters with the drainage channel, and compare the numerical results with the experimental results. Compared the numerical results with the experimental results, the numerical results agree well with the experimental results. The numerical and experimental results reveal that the proposed single and double submerged breakwaters with the drainage channel reduces the surface elevation behind the submerged breakwater and rip currents flowing offshore through the open inlet between double submerged breakwaters. Therefore, we see that, the rip currents, that cause scour around the lower part of the open inlet and affect the stability of the submerged breakwaters, can be reduced by installing a drainage channel.