Theoretical and experimental investigation on wave interaction with a concentric porous cylinder form of breakwater

This paper aims at deriving velocity potential for the regular wave passing through a concentric porous cylinder system, which has an arbitrary smooth section. The wave interaction with the structures, for instance wave force on them and wave elevation, are discussed with different sections and wave properties in this study. The efficiency and accuracy of present method was validated by comparing with the semi-analytical method of SBFEM first. Then an experiment with a quasi-ellipse caisson was also performed to demonstrate the effectiveness and practical potential of present method. Finally, a surface-piercing concentric cylindrical system, which consists of an impermeable inner cylinder and a coaxial single-layered perforated cylinder, was investigated by using present method. The analysis shows that the maximum wave force on the inner cylinder is reduced to some extent with a noncircular perforated cylinder around it, compared with circular cases, while the wave run-up is enlarged by the uneven spacing between the boundaries with the increasing of the wave number.