Diffraction of Regular and Irregular Waves by a Horizontal Cylinder in a Fully Nonlinear 2D Numerical Wave Tank using Desingularized BEM

摘要

An approach for two-dimensional (2D) numerical wave tank (NWT) in the time domain is developed within the frame of potential flow, in which the fully nonlinear (or exact) free surface boundary conditions are satisfied. In this approach, the desingularized boundary element method (BEM) is employed to solve the boundary value problem at each time step. The fourth-order predictor-corrector Adams-Bashforth-Moulton (ABM4) scheme is used for the time-stepping integration of instantaneous free surface boundary conditions. A damping layer near the end-wall of wave tank is added to absorb the outgoing waves. The saw-tooth instability is overcome via a five-point Chebyshev smoothing scheme. The present model is applied to study the diffraction problem of both regular and irregular incident waves by a horizontal cylinder in detail.