Scattering of Oblique Surface Waves by Permeable Barriers

Abstract

The scattering of oblique incident surface waves by permeable vertical barriers in water of finite depth is investigated for four different barrier configurations: (1) a bottom-standing barrier; (2) a surface-piercing barrier; (3) a barrier with a gap; and (4) a submerged barrier. The boundary-value problems are converted to dual/triple series relations by suitable application of the eigenfunction expansion method, and then the full solutions are obtained by the least-square approximation method. The variations of reflection coefficients, hydrodynamic pressure differences along the two sides of the barriers, and surface elevations are obtained for different values of the wave-effect parameter, the porous-effect parameter, as well as the angle of incidence. It is observed that the finite angle of incidence as well as the porous effect of the barriers reduce the reflection of the incident waves imparted on the barriers, the wave amplitude, and the hydrodynamic pressure exerted on the barriers. 3D wave features are also observed as the surface waves pass through the barriers.