波浪与多柱结构物的非线性相互作用

摘要

The fully nonlinear wave potential theory is employed to analyze interactions between water waves and multiple or a group of cylinders based on the finite element method (FEM)for the nearly trapped mode.Wave run-up and hydrodynamic forces on the structure are obtained.The nonlinear free surface boundary conditions are satisfied on the instantaneous free surface and body surface.The velocity potential problems at each time step are solved through the FEM.The velocity on the free surface is calculated through a difference method.The matrix equation of the FEM is solved through the conjugate gradient method with a symmetric successive overrelaxlation preconditioner and the initial solution is obtained from the result at the previous time step.Results for various configurations are provided to show the effect of the interaction and their behaviors near the trapped modes.%基于全非线性势流理论，采用无结构网格的有限元法对近俘获波现象进行数值模拟，选择多柱结构物为研究对象来研究近俘获波现象，通过数值模拟计算结构物处的波浪爬高及作用在结构物上的水动力载荷、自由表面和物面条件在其瞬时位置满足。每一时步上的速度势通过求解有限元方程获得，而自由表面速度则采用差分法来计算以提高计算效率。对有限元方程采用预条件共轭梯度法来求解。