Dissipation of gravity waves due to submerged porous plate coupled with porous structures

The present study focuses on the wave trapping due to the submerged horizontal porous plate combined with bottom-standing porous structure and surface-piercing porous structure. The submerged plate thickness is considered to be negligible as compared to the incident wavelength and water depth and the porous structure is considered to be of finite width. The orthogonal mode-coupling relation is used to analyse the wave interaction with the combined structure. The reflection, transmission and dissipation coefficients along with wave force on the porous structure and surface deflection in the incident and transmitted region is investigated for the study of hydrodynamic performance of the composite porous breakwater system. Further, the effect of porosity of submerged plate and structure, friction factor, submerged depth of plate and structure angle of incidence and gap between the submerged plate and porous structure are investigated to analyse the effective wave dissipation by the porous breakwater system. In addition, the comparative study of the present method is performed with the results available in the literatures. The study noted that wave damping due to the submerged porous plate backed by surface-piercing porous structure is more as compared to the submerged porous plate backed by bottom-standing porous structure. The study will be helpful to scientist and engineers in the design of suitable composite breakwater system for wave attenuation in the coastal region.