Experimental and numerical evaluation of chambered porous barriers in the presence of seawall

The gravity wave scattering phenomena attributed to porous breakwaters are analyzed using experimental and numerical investigations. Three different configurations, such as traditional Jarlan-type, single-chambered, and dual-chambered porous breakwaters (modified Jarlan-type), are explored for their energy damping across the range of design parameters. The experimental findings are utilized to validate the numerical model developed using the dual boundary element method within the framework of linear wave theory. Linear and quadratic pressure drop boundary conditions are employed to capture the energy loss due to viscous and inertial effects. Notably, the dual-chambered porous breakwater excels in performance over the presented alternatives, which is plausibly predicted by the quadratic pressure drop boundary condition. Furthermore, the present study leverages the benefits of a partially extended vertical inner barrier to develop the dual-chambered breakwater system, and it shows the minimum reflection (KR) of 0.133 as the porosity is confined to 0.2. The energy dissipation (KD) for the relative horizontal plate submergence (S/h) of 0.375 remains high across most wavelengths, with a peak of 0.98. The dual-chambered breakwater having 0.2 porosity shows a 55% enhanced reduction in wave reflection compared to the 0.4 porosity and a 51% better reduction in wave reflection compared to the conventional Jarlan-type breakwater of 0.2 porosity. Overall, the analysis concludes that the dual-chambered porous breakwater could be a highly effective coastal protection structure, due to its substantial attenuation of incident wave impact.