船体在波浪中的非线性水动压力

本文提出了一个预报船体在波浪中大幅运动时非线性水动压力场的二维时域理论。船体扰动势用时域自由面格林函数和在入射波下的瞬时湿表面上的分布源求解；与非线性水动压力场相匹配的船体运动用差分法求得。为提高计算效率和避免数值过程发散，采用了改进的数值模型和方案。通过线性理论计算与模型试验结果的比较，指出了线性切片理论在预报水动压力场时的不足，水动压力与波高的非线性关系及正负水动压力沿船体表面的分布在Wigley船的计算比较中得到了说明。初步计算表明，该理论的实用化发展前景是令有鼓舞的。相应的计算机程序可在PC机上运行。

Nonlinear Hydrodynamic Pressures on Ship Hulls in Waves

A two-dimensional time-domain nonlinear strip theory is developed for predicting nonlinear hydrodynamic pressures and associated ship motions in large amplitude regular waves. The problem is solved with time-domain free-surface Green function and source distributions on instantaneous wetted hull surface in incident waves. Improved numerical model and scheme are employed to avoid divergence and enhance efficiency during simulation procedures. The emphasis is placed on the nonlinear hydrodynamic pressures on instantaneous body surface under incident waves and the consistence of ship motions and hydrodynamic forces that are achieved with a differential numerical scheme. The drawbacks of linear strip theory in predicting hydrodynamic pressures are pointed out with the comparisons of predicted and model test results. The nonlinear phenomena of hydrodynamic pressures with wave heights and the distributions of the positive and negative hydrodynamic pressures are illustrated with predicted results of a Wigley ship. The primary calculation shows encouraging prospect for further development of the theory and its application.