波 流 与 结 构 物 相 互 作 用 的 数 值 模 拟

A time-domain numerical model is established by a higher-order boundary element method to study the problem of wave-current action on arbitrary 3D bodies. Under the assumption of small flow velocity, the velocity potential is expanded by a perturbation method. The boundary value problem is decomposed into a steady double-body flow problem at the zero-order of wave steepness and an unsteady wave problem at the first-order of wave steepness. The velocity potential on the body surface and the derivative of the velocity potential on the free surface are then given as the solution of a higher order boundary element integral equation, which is solved by a numerical code. A 4th-order Runge-Kutta method is applied for the time marching. An artificial damping layer is adopted to dissipate the scattering waves. Validation of the numerical method is carried out on wave forces, run-up and mean drift forces of wave-current acting on a bottom-mounted vertical cylinder. The present results are all in close agreement with the results of a frequency-domain method and a published time-domain method. Subsequently, this model was applied to investigate the problem of wave-current interaction with actual engineering structures.