Computational Techniques of 2D Tidal Flow in Estuaries and Bays

- Some problems in the numerical calculation of tidal flow in estuaries and bays, such as distribution bed roughness, relationship between model moving boundary and water volume balance, remedy of certain shortage under open boundary conditions, smooth transfer of the controlling message for the inner boundaries of nested model, can not be solved usually by means of the fundamental equations and computing mode adopted in the numerical model, but can be done by the measures which not only satisfy the physical features but also are convenient for operation. Based on the calculated samples of some areas of Modaomen, Lingdingyang and Huangmaohai of the Pearl River Estuary, and Shuidong Bay (a typical barrier- lagoon tidal channel) in Guangdong Province, method and process of calculation for the above mentioned problems are briefly presented in this paper.     

Numerical Simulation for Refraction-Diffraction of Waves in Water of Slowly Varying Current and Topography

A new numerical finite difference iteration method for refraction-diffraction of waves in waterof slowly varying current and topography is developed in this paper.And corresponding theoretical modelincluding the dissipation term is briefly described,together with some analysis and comparison ofcomputational results of the model with measurements in a hydraulic scale model(Berkhoff et al.,1982).An example of practical use of the method is given,showing that the present model is useful to engineeringpractice.     

Computation of Diffraction of Irregular Waves Behind Single Jetty

- This paper presents a calculation method for the diffraction of both regular waves and irregular waves of the single directional frequency spectrum behind a single jetty with a theoretical analysis, which has been confirmed through the model experiments, derives a method of computing the diffracted irregular waves behind the single jetty with the theoretical analysis on the basis of computation of the field data and gives the formulas and the figures of the computation of wave diffractions behind the vertical wall or mound single jetties.     

34万吨级FPSO的中横剖面优化设计

以中横剖面的面积最小为目标函数，应用自适应步长随机搜索法，对34万吨级FPSO中横剖面进行了优化设计，并将规范设计结果和优化设计结果进行了比较，优化效果较好。     

地理信息系统在海水养殖环境研究中的应用

本文概述了目前我国海水养殖环境所面临的主要问题，分析了GIS技术及其在养殖水域生态环境研究中的功能和作用，尝试性地探讨了GIS技术的数据收集、管理和分析的强大功能在养殖水域生态环境研究中的若干应用及其发展前景，并以广东考洲洋养殖水域的环境监测作为示例加以阐述。     

Long Waves Induced by Wave Groups over a Trench

The second order long waves of the mean water free surface displacement induced by the wave groups over a trench are discussed in this paper. The incident wave groups are supposed to be superposed by 2 linear waves with different amplitudes, phases and slightly different frequencies. Some of the theoretical formulas and numerical results are presented.     

Free vibrations of a cantilever beam with a spring–mass system attached to the free end

An exact solution for the title problem is obtained using the Bernoulli–Euler theory of beam vibrations. Natural frequencies are obtained for a wide range of the intervening physical parameters. The problem is of interest in naval and ocean engineering systems since in order to avoid dangerous resonance conditions the designer must be able to predict natural frequencies of the overall mechanical system: structure–motor and its elastic mounting.     

Experimental Research of Hexagon Multihole Armour Block on Breakwater

This paper introduces a new kind of armour block - hexagon multihole block on sloping breakwater. It has great characteristics such as good interlocking, strong resistance against waves and saving concrete. Through the hydraulic model test, the mechanism of stability of the block has been proved and the relations between stability and wave height, wave period, water depth, slope, laying method, porosity and cushion have been found. The effect of weight on steadiness have also been discovered. Finally, the method of design and some formulas are given.     

Asymptotic Analysis Methods for Structural Reliability

- Applying Laplace asymptotic approximation of integral, asymptotic analysis methods of structural reliability are proposed in generalized and orthogonal random space. Analytic results show that the proposed methods are simple in calculation and accurate enough for problems of continuous random variables.     

Uplift Pressure of Waves on A Horizontal Plate

1 .IntroductionOwingtotheneedfordevelopingoffshoreresources,moreandmorehollow trussedstructuresareconstructed ,suchasalongshorequays ,islandquays,artificialislands ,bollards ,maritimeplatforms ,etc .Thelargeentitypartofthosemaritimestructuresusuallyconsistsofahorizontalplateabovethestillwaterlevel,anditusuallysuffersfromwaveattacksandthuscaneasilybedestroyed .Toavoidsuchakindofaccidents ,themostimportantistoaccuratelyevaluatetheupliftpressuresofwavesontheplateundervariouswaveconditionsandbound…