Scattering of water waves by surface-piercing barriers using dual BEM

The primary purpose of this paper is using the dual boundary element method (dual BEM) to analyze the reflection and the transmission of water waves resulting from a rectangular block, a single vertical thin barrier, a system of vertical, equally spaced, thin barriers, and thin barriers of specific shape (e.g., type L, T, T1, FR, FL and type ┌┐). The present model is formulated and applied to study the effects of surface-piercing barriers, which are modeled as zero-thickness structures. Two-dimensional problems are considered, and the linear gravity wave theory is used. Furthermore, the accuracy and the validity of the present method have been verified by comparing results with: (a) numerical results obtained from published analytical solutions, (b) other numerical results and (c) reliable experimental data. A very good agreement is observed. Finally, the reflection and transmission coefficients of all the examined configurations of barriers for various wave conditions are presented and discussed. The results show that the reflection coefficient steadily increases up to unity for the single barrier as the wavenumber increases while for the double barriers reflection coefficient oscillates between 0 and 1. For specific shape, there will be no phase difference problem for type L, so the transmission coefficients of type L are smaller than those of type T and T1. The performance characteristics indicated that the surface-piercing barriers may be beneficial to the design of the marine infrastructures in the future.