WAVE ACTION ON A PARTIALLY PERFORATED WALL BREAKWATER WITH AN INTERNAL HORIZONTAL POROUS PLATE

摘要

A partially perforated wall breakwater with an internal submerged horizontal porous plate is proposed and studied in this paper. An analytical solution based on the linear potential theory is developed to assess the wave absorbing capacity of the new structure.According to the components of the breakwater, the whole fluid domain is divided into three sub-domains, and the velocity potential in each domain is obtained by means of the matched eigenfunction method. Then the unknown expansion coefficients are obtained by matching the boundary conditions on the front wall, and the reflection coefficient are subsequently determined.The present numerical results for limiting cases are exactly the same to the previous predictions of a fully perforated wall breakwater with a submerged horizontal solid plate (Yip and Chwang,2000) and a partially perforated wall breakwater without the internal horizontal plate (Li et al.,2002). Numerical results show that with suitable geometrical porosities of the perforated front wall and the horizontal porous plate, the reflection coefficient will be always small if the relative wave absorbing chamber width (distance between the front and back walls versus incident wavelength) exceeds a certain small value.