T. L. Yip

Scattering of surface waves by a semi-infinite floating elastic plate

A new inner product is developed based on the Fourier analysis to study the scattering of surface waves by a floating semi-infinite elastic plate in a two-dimensional water domain of finite depth. The eigenfunctions for the plate-covered region are orthogonal with respect to this new inner product. The problem is studied for various wave and geometrical conditions. Especially, the influence of different edge conditions on the hydrodynamic behavior is investigated and compared. The edge conditions considered in the present study involve (i) a free edge, (ii) a simply supported edge, and (iii) a built-in edge. The hydrodynamic performance of an elastic plate is characterized for various conditions in terms of wave reflection and transmission, plate deflection, and surface strain. It is observed that the hydrodynamic behavior depends on the wave conditions, the geometrical settings, and the edge conditions. The built-in edge condition induces the maximum wave reflection and the minimum wave transmission. The...

Trapping of surface waves by porous and flexible structures

Abstract The trapping of surface waves by submerged vertical porous and flexible barriers near the end of a semi-infinitely long channel of finite depth is investigated. The barrier configurations include a bottom-touching barrier and a surface-piercing barrier. In the case of a bottom-touching barrier, the barrier is clamped at the bottom and is free at the upper end. While in the case of a surface-piercing barrier, the barrier is clamped by a structure above the free surface and is free at the lower end which is inside the water. By matching the velocity and pressure along the barrier and along the gap and using the edge conditions at the end points, systems of linear equations are obtained. In the case of a surface-piercing barrier, the deflection, slope of deflection, the bending moment and the shear force acting on the barrier are assumed to be continuous at the interaction point where the barrier and the free surface meet each other. The reflection coefficients are obtained and discussed for various wave conditions, geometrical settings, and barrier properties. The hydrodynamic force and the overturning moment on the barrier and the deflection of a flexible barrier are calculated and analysed for different cases.