Interaction between solitary waves and a combined structure of two concentric asymmetric porous arc walls

Abstract

An analytical model based on the linear potential flow theory is developed to study the diffraction problem of solitary wave interaction with a combined structure of two thin concentric asymmetric porous arc walls. The two closed virtual circles, where the two arc walls are located, are used to partition the entire fluid region into three sub-regions; the velocity potentials associated with each region are expanded in terms of a series of appropriate eigenfunctions. Furthermore, a series of simultaneous equations are used to determine the unknown coefficients in the expressions of the velocity potentials. The accuracy of the present model is verified by comparing its output with published results. Meanwhile, the impact of various important parameters (i.e., annular spacing, incident angle, the orientation of two arc walls, and porosity of walls) with respect to wave forces and relative wave height is examined. Numerical results reveal that dual-arc walls provide more significant protection for the interior cylinder than single walls. The two cross-placed arc walls provide excellent protection for the interior cylinder with their sheltered area extended. This research is anticipated to provide useful theoretical guidance for nearshore engineering design.