A General Linear Wave Theory for Water Waves Propagating over Uneven Porous Bottoms

Starting from the widespread phenomena of porous bottoms in the near shore region, considering fully the diversity of bottom topography and wave number variation, and including the effect of evanescent modes, a general linear wave theory for water waves propagating over uneven porous bottoms in the near shore region is established by use of Green‘s scond identity. This theory can be reduced to a number of the most typical mild-slope equations curreutly in use and provide a reliable research basis for follow-up development of nonlinear water wave theory involving porous bottoms.     

Mach Effect of Oblique Nonlinear Irregular Waves Interacting with Vertical Walls

Based on Hong‘s theory, previous random models, and a generalized expression suitable for FIT calculation, the interaction between irregular waves and vertical walls is numerically simulated. The results of simulation demonstrate that the wave energy changes with the incidence angle and the distance from the wall. Particularly, the Mach effect and the combined wave spectrum characteristics are analyzed in detail, which are significant in both theory and practice.     

Probabilistic Models for the Probability of Wave Breaking and Whitecap Coverage Based on Kinematic Breaking Criterion

More and more researches show that neither the critical downward acceleration nor the critical slope of water waves is a universal constant. On the contrary, they vary with particular wave conditions. This fact moders the models either for the probability of wave breaking B or for the whitecap coverage W based on these criteria difficult to apply. In this paper and the one which follows we seek to develop models for the prediction of both B and W based on the kinematical criterion. First, several joint probabihstic distribution functions (PDFs) of wave characteristics are derived, based on which the breaking properties B and W are estimated. The estimation is made on the assumption that a wave breaks ff the horizontal velocity of water particles at its crest exceeds the local wave celerity, and whitecapping occurs in regions of fluid where water particles travel faster than the waves. The consequent B and W depend on wave spectral moments of orders 0 to 4.Then the JONSWAP spectrum is used to represent the fetch-limited sea waves in deep water, so as to relate the probahility of wave breaking and the whitecap coverage with wind parameters. To this end, the time-averaging technique proposed by Glazman (1986) is applied to the estimation of the spectral moments involved, and furthermore, the theoretical models are compared with available observations collected from published literature. From the comparison, the averaging time scale is determined. The final models show that the probability of wave breaking as well as the whitecap coverage depends on the dimensionless fetch. The agreement between these models and the database is reasonable.     

海面的电磁散射模型及应用

本文采用随机格林函数方法求解了电磁场随机波动方程,给出了具有倾斜表面含气泡海浪的体散射系数表达式,并且指出,当电磁波近垂直入射时,只应用面散射模型是不充分的,必须考虑体散射效应.同时讨论了当入射角在20°～30°之间体散射系数与面散射系数的加权对接问题,给出了完整的海面散射系数计算过程.     

基于塑性极限分析理论和神经网络响应面的结构系统可靠性分析

根据多层神经网络映射存在定理，提出了基于神经网络响应面和塑性极限分析理论的结构系统可靠性分析的新方法。数值试验表明，该方法可以快速、高质量地求出结构系统可靠性指标，是一个具有发展前景的新方法。     

香港附近海区台风波浪的波群统计分析

根据香港附近海区１９８５，１９８６年两次台风大浪的实测资料，以有效波高为相应水平，对波群作统计分析，得出可供海洋工程参考的波群连长、波群重复长度、波群出现频率以及波群中最大波高与有效波高的关系等。并将统计值与理论值作比较，结果表明：统计值大于“连”的理论值，而与包线理论中采用合田修正公式的汁算值相近。     

不规则波折射物理模型试验研究

作者曾发表过“不规则波折射的数学模型〔１〕。为了与数学模型的计算结果相互验证，在大连理工大学海岸及近海工程国家重点实验室进行了不规则波折射物理模型试验。试验研究结果表明：提出的“不规则波折射数学模型”对频谱采用等能量分割、对方向分布采用等间隔（Δθ＝ｃｏｓｎｔ）分割的组成波折射线性叠加法是合理的、可行的，可供港口及海岸工程规划、设计应用     

海洋测绘基准的需求及现状

研究了海洋测绘基准的需求问题，从几个方面探讨了建立海洋测绘基准的必要性和具体方法，介绍了深度基准面的确定方法以及海洋测绘基准发展的现状、存在的问题和解决的对策。     

先锋孤立子生成的理论平均波阻(Ⅰ).理论

根据作者导得的AfKdV方程，理论上确定了先锋孤立子生成问题的理论平均波阻，能量劈分及能量劈分比。本文的能量劈分是确定先锋孤立子生成参数的理论基础。同时，本理论确定了现有理论中的自由未知参数问题，从而使先锋孤立子生成参数得到理论预报。     

不规则波的物理模拟

介绍了不规则波的生成方法，其中长波、反射及三皮是关键。对波－－充合成做了分析，讨论了水波中的与雷诺数有关的现象的模拟。