Ali Haghighat - M.Sc student of offshore structures Tehran University
Moharram Dolatshahi - Civil Engineering Group Tehran University

In present research, the diffraction of solitary waves by a semi-infinite thin and solid breakwater in water of uniform depth is studied with numerical method. Particular interest is focused on the nonlinear effects and the despersive effects in this fully three-dimensional problem of strong interaction between a solitary wave and a solid structure )breakwater). For solving this problem, the generalized boussines (GB) two equation model is applied to calculate the flow potential and the wave free-surface elevation. Following the incident solitary waves impinging on a breakwater, the subsequent evolution of the transmitted, reflected, and diffracted wave fields are numerically evaluated by FDM predictor-corrector Adams (Moulton). It is found that after interaction with the breakwater, an initially plane solitary wave is diffracted as a three-dimensional cylindrical solitary wave and propagates with uniform amplitude toward the shadow region. The newly evolved secondary back-scattered and forward-scattered wave generated from the tip of the breakwater propagate outward and follow the leading reflected wave and diffracted wave, respectively. The present results are in good agreement with the experimental data.