Analytical solutions for diffraction and radiation problems of an infinitely long floating compound breakwater with wide porous media

Abstract

Presented herein is the analytical formulation for obtaining the hydrodynamic solutions of an infinitely long floating compound breakwater with wide porous media. Both the diffraction and radiation problems are tackled and the eigenfunction expansion method is used to obtain solutions based on the linear potential theory. The present formulation is versatile as floating box-type and compound-type breakwaters can be treated in the same formulation by changing porosity ε. The analytical solutions obtained by the present method are first verified for two limiting cases (ε=0or1) by using the authors’ numerical computer algorithm. Next, for the intermediate cases with porosity ranging between 0 and 1, the wave exciting forces are evaluated at the near-field and far-field. This implies that if the results obtained in two independent ways are agreeable, it can be said that both the diffraction and radiation problems are correctly solved. By using the verified formulation, parametric studies are conducted to investigate the wide porous media effects on major hydrodynamic quantities of a floating compound breakwater. The present formulation is useful as a benchmarking tool when developing a numerical algorithm or conducting an experiment for a floating breakwater with wide porous media.