Wave dissipation over a horizontal slotted plate with a leeside vertical seawall: analytical and numerical approaches

Abstract

In this study, the wave energy dissipation over a horizontal slotted plate with a leeside vertical seawall was extensively investigated by analytical and numerical approaches. The analytical model was developed by using the matched eigenfunction expansion method and the energy dissipation model with a porosity-dependent drag coefficient estimated by computational fluid dynamics (CFD) results from the 2D channel flow with symmetric slats. The energy dissipation of a horizontal slotted plate was assessed by analyzing the variation of the reflection coefficient, wave run-up, vertical wave force on the plate, and horizontal wave force on the vertical wall for different submergence depths, porosities, plate lengths, and wave steepnesses. Results from the analytical model were compared extensively with those from CFD simulations. CFD computations were performed by using an incompressible turbulence model based on Reynolds averaged Navier–Stokes equations and volume of fluid method. Overall, a good agreement was observed between the analytical and CFD results. A qualitative numerical analysis showed that the wave dissipation over a horizontal slotted plate was caused by the generation of higher-harmonic waves, wave breaking, and vortices formation near the slotted plate. The presented analytical and numerical models would provide a mutually complementary tool for the accurate and efficient design of a horizontal slotted plate for reducing the reflection coefficients, wave forces, and wave run-up on seawalls.