Surface and Interfacial Wave Propagation over an Undulating Bottom in a Stratified Fluid with a Moored Porous-Flexible Barrier

Abstract

This work investigated the effect of a porous and flexible barrier and undulating bottom on wave attenuation in a two-layer stratified fluid under the action of oblique wave incidence, using small amplitude and structural response theory. Two sets of problems with porous and flexible barriers in the absence and presence of impervious sea-wall are discussed. Two different barrier configurations, called bottom-standing and surface-piercing, were considered. The Fourier method, least-square approximation method, and mild-slope approximation method were used to tackle the physical problem. The study reveals an optimal mooring angle to prevent its deformation by surface and interfacial waves. The dissipation of interfacial waves by bottom-standing and surface-piercing barriers exhibits an inverse pattern. Comparatively longer bottoms are insensitive to the interfacial wave-induced forces on the barrier when the depth ratio changes. The contribution of inertial effects in barrier porosity is seen to be critical in protecting existing offshore structures or sea-wall. The sea-wall can be protected using bottom-standing and surface-piercing barriers in a situation of higher surface and interfacial wave energies, respectively.