Scattering of surface waves by a submerged wavy porous plate floating over sea-bed undulations under oblique waves

Abstract

In the present study, we investigated the effectiveness of a submerged wavy porous plate (WPP) of finite thickness floating over seabed undulations subject to the action of oblique incident waves under the assumption of linear potential flow theory. Three different cases, such as (a) WPP placed over the flat seabed, (b) WPP placed far away from the rippled seabed, and (c) placed beneath the rippled seabed, have been considered to analyze the wave scattering by the WPP. The motion of the wave within the thick WPP is modeled using the well-established Sollitt and Cross model. The multidomain boundary element method (BEM) is employed to obtain the numerical solutions of the associated boundary value problem. In addition, the impact of various parameters, such as the depth of submergence of the WPP, the incident wave angle, the porosity of the thick place, and the width of the breakwater, on scattering coefficients such as wave reflection, transmission, wave energy dissipation and vertical force on the WPP is analyzed for a wide range of wave frequencies. The results suggest that introducing structural porosity in the wavy plate effectively reduces wave reflection coefficients for a wide range of frequencies and increases the dissipation of incident wave energy by about 80%. The energy loss is observed to be high for the plate with porosity 10% in the long wave regime. The Bragg resonance occurred for certain wavenumbers, with the amplitude of the response being the same irrespective of the variations in the angle of incidents for the impermeable wavy plates.