Water Wave Refraction and Diffraction over Frictional Topography     

Zuo Qihua  Yao Guoquan Ding Bingcan Senior Engineer  Nanjing Hydraulic Research Institute  Nanjing Engineer  Nanjing Hydraulic Research Institute  Nanjing 《中国海洋工程》1993,(1)

- This paper considers the effects of wave energy dissipation induced by sea-bottom friction on the computational results of water wave refraction and diffraction with the parabolic equation method. The presented results show that the friction factor formula adopted in this paper is of higher numerical accuracy than that introduced by Dalrymphe (1984), and it can be used to compute wave propagation over large open areas.  相似文献   

Reliability Index of Caisson Breakwaters for Load Variables Correlated   总被引：1，自引：0，他引：1  

郄禄文  李炎保 《中国海洋工程》2004,18(4):577-584

In order to suit the condition that the wave uplift is correlated with the horizontal wave load acting on a vertical breakwater, a generally used method for determining the reliability index β of the breakwater, i.e. the Hasofer-Lind method, is extended in a generalized stochastic space for correlative variables. The computational results for a caisson breakwater indicate that the value of β for the case of correlated variables is obviously smaller than that for the case of independent variables.  相似文献   

Nonlinear Analysis of Nearshore Wave Height Variation Due to Shoaling     

Shen Xianrong Engineer  Zhejiang Provincial Design Institute of Communications  Hangzhou 《中国海洋工程》1995,(4)

Wave formulae derived from the dispersion relation for cnoidal waves are used to find an analytical solution to the problem of nearshore wave height variation on a simple topography, i. e., with an incrementally constant slope. The solution accounts for shoaling, frictional dissipation and will be sufficiently accurate for practical purposes considering the simplified assumptions which are necessary for the treatment of this problem by any method.  相似文献   

Coupled BEM-FEM Analysis of the Large-Diameter Cylinder Structure System   总被引：2，自引：0，他引：2  

Zhou Xireng  Duan Xudong  Sang Xuezhu Zhang Rui  Dai Jialu Professor  Tianjin University  Tianjin Engineer  Xiamen Port Office  Fujian Lecturer  Tianjin University  Tianjin Senior Engineer  Tianjin Port Office  Tianjin 《中国海洋工程》1992,(2)

A method of coupled BEM-FEM analysis for the elastic spatial structure system is presented. It can be applied to the calculation of the stress and deformation of the large-diamater cylinder structure system and it is suitable for symmetric or non-symmetric structures under the distributed or concentrated load. Numerical examples show that the proposed method and computer program BEFEM are quite efficient in the analysis of the large-diameter cylinder structure problems in ocean engineering.  相似文献   

Method to Determine Depositional Range of Sediment Transported from Multiple Sources in Water Area   总被引：1，自引：0，他引：1  

Ying Qiang  Jing Fei Ma Jin Rong Engineer  Nanjing Hydraulic Research Institute  Nanjing Lecturer  Nanjing College of Navigation Engineering  Nanjing Assistant Engineer  Nanjing Hydraulic Research Institute  Nanjing 《中国海洋工程》1995,(3)

- The sediment from different sources have different content of the characteristic elements. According to the fuzzy mathematical theory, corresponding calculation and cluster analysis of each sediment sample are carried out, so the main courses of sediment transport in water area can be obtained. The characteristics of sediment from different sources are analysed. It is found that the sediment deposited of certain point in water area is due to the sources' contributions which can be calculated by the formula derived in this paper. Based on the distribution of the contribution values, the depositional range of sediment from each source can be determined. The depositional range in Huangmao Bay is determined as an example.  相似文献   

A New Method of Surveying Underwater Parts of Self Elevating Drilling Platform     

Cong Zheyan Ji Liangying Senior Engineer  Bohai Engineering & Design Company  Shanghai Senior Engineer  Shanghai Shipyard  Shanghai 《中国海洋工程》1991,(1)

It is a new method of surveying leg spuds of self-elevating drilling platforms to lift them out of water with the help of additional middle guide blocks. Its main advantages in comparison with other methods normally used up to now are: less expensive, time saving, no need for specially designated water area, direct visual observation, good reliability and safety. The working principle has been presented with the example of two platforms "Bohai No. 8" and "Bohai No. 10", to which the method was used. Also a comprehensive comparison with other methods in technological and economical aspects is given in the paper.  相似文献   

A Modified Quasi-Static Method for CALM System Analysis     

Xie Wei Tang Xinming Engineer  China Offshore Oil Development & Engineering Corporation  Tianjin 《中国海洋工程》1993,(3)

The quasi-static analysis method introduced by API RP 2P is well known and accepted as a very useful mooring analysis method. In the early design stage, this method is widely used for preliminary analysis and mooring parameter selection. However, the quasi-static method of API RP 2P is developed for single-floating-body condition, i. e., only one floating body is considered in the computation procedure. Difficulties arise when it is used for the analysis of a CALM system, which is comprised of two floating bodies (tanker and buoy). This paper presents an analysis procedure for a two-floating-body system based on the quasi-static procedure of API RP 2P with some modifications reflecting special characteristics of the CALM system. Finally, the analysis results of a CALM system are given to illustrate the use of this procedure.  相似文献   

Fuzzy Risk Analysis of Harbour Engineering Investment by Hierarchy System Approach     

Lin Shaopei  Zhang Zhongming Professor  Civil  Architectural Engineering Dept.  Shanghai Jiao Tong University  Shanghai Lecturer  Civil  Architectural Engineering Dept.  Shanghai Jiao Tong University  Shanghai 《中国海洋工程》1992,(1)

The present risk analysis model of engineering investment is built by fuzzy hierarchy approach under the assumption of maximizing the revenues of the project during its whole life cycle of operation. It can reasonably be expressed by a system evaluation analysis. As a matter of fact, the system, aimed by its system goal can be modelled by a set of factors, constitutively structured by certain links between them, to form a factorial network chart, which represents the essentials of the system behaviours, the nodes of which represent the factors concerned. The weight distribution between factors located at the same level can be determined by the eigen-value problem of a "pair comparison" relation matrix. The weight distribution of factors at each level is successively manipulated until the fuzzy synthetic risk assessment. As an example of risk analysis of engineering investment, a harbour construction project is presented for illustration.  相似文献   

Influence of Energy Directional Spread on Wave Spectral Refraction     

Li Yucheng Professor  Dept. of Civil Engineering  Dalian University of Technology  Dalian 《中国海洋工程》1992,(2)

Pierson- Moskowitz Spectrum, JONSWAP Spectrum as well as Bretschneider- Mitsuyasu Spectrum are used in this paper for analyzing the influence of wave energy directional spread on refraction of wave spectrum due to both current and topography of sea bed. The author's calculation indicates that such kind influence on the characteristic value of wave height as well as the average direction of wave energy propagation can not be ignored.  相似文献   

Some Considerations in Design and Construction of the Wei-Liu Water Supplying Submarine Pipeline     

Fan Yunlin  Chang Dezhi Associate Professor  Dept. of Ocean Eng.  Tianjin University Engineer  Construction Committee of Weihai City  Shandong Province 《中国海洋工程》1991,(4)

The Wei- Liu water supplying submarine pipeline is at present the longest one of the kind in China. It is about 4 kilometers long from Weihai City to Liugong Island in Shandong province. It took only half a year to design and construct it. The project was of a high economic efficiency and some practical experiences were achieved. In this paper a general introduction to the design and construction of this pipeline is presented and such problems as the stability of the pipeline in very soft clay, design of curved slide for launching and estimation of dragging forces are expounded.  相似文献