Investigation of Internal Turret Mooring System for Oil Production Storage Vessels     

Ma Zhiliang  Huang Xianglu  Ma Peisun Fan Genfa  Yu Xiangsan  Jin Dexian Professor  Shanghai Jiao Tong University  Shanghai Associate Professor  Shanghai Jiao Tong University  Shanghai Research Fellow  Shanghai Jiao Tong University  Shanghai 《中国海洋工程》1991,(4)

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Finite Element Analysis of soft Foundation Strengthening by Vacuum Loading from Lower Position     

Qiu Changlin Yan Shuwang Ph. D. Student  Dept. of Hydraulic Engrg.  Tianjin University  Tianjin Professor  Dept. of Hydraulic Engrg.  Tianjin University  Tianjin 《中国海洋工程》1997,(1)

Strengthening soft foundation by vacuum loading from lower position is a new method of ac-celerating the consolidation of dredger fill.This paper presents the mechanism of soft foundation strength-ening by vacuum loading from lower position and evaluates the effectiveness of this method under variousboundary conditions by means of finite element method(FEM)on the basis of Biot's consolidationtheory.  相似文献   

High-Order Models of Nonlinear and Dispersive Wave in Water of Varying Depth with Arbitrary Sloping Bottom   总被引：4，自引：0，他引：4  

Hong Guangwen Professor  Coastal  Ocean Engineering Research Institute  Hohai University  Nanjing  P. R. China. 《中国海洋工程》1997,(3)

High-order models with a dissipative term for nonlinear and dispersive wave in water of va-rying depth with an arbitrary sloping bottom are presented in this article.First,the formal derivations toany high order of μ(=h/λ,depth to deep-water wave length ratio)and ε(=α/h,wave amplitude todepth ratio)for velocity potential,particle velocity vector,pressure and the Boussinesq-type equations forsurface elevation η and horizontal velocity vector U at any given level in water are given.Then,the exactexplicit expressions to the fourth order of μ are derived.Finally,the linear solutions of η,U,C(phase ce-lerity)and C_g(group velocity)for a constant water depth are obtained.Compared with the Airy theory,excellent results can be found even for a water depth as large as the wave legnth.The present high-ordermodels are applicable to nonlinear regular and irregular waves in water of any varying depth(from shal-low to deep)and bottom slope(from mild to steep).  相似文献   

Investigation on Settling Characteristics of Floes in the Changjiang Estuary, China     

Li Yan  Wang Yaqin LinYian Associate Professor  Second Institute of Oceanography  State Oceanic Administration  Hangzhou  Senior Engineer  Second Institute of Oceanography  State Oceanic Administration  Hangzhou 《中国海洋工程》1995,(3)

- Settling characteristics of floes, including relative settling velocity, relative flocculation coefficient and flocculation exponent, are obtained by the suspended load equations for different size fractions. Data of the Changjiang Estuary suggest that level of flocculation changes from river section, river mouth (turbidity maximum) to offshore area in sequence of low, very high and high. The settling characteristics of floes reflected by in situ estimation performs a similar feature as that obtained from still water experiment.  相似文献   

The New Form of Time-Dependent Mild Slope Equation for Random Waves     

Zhang Yonggang  Li Yucheng Teng Bin Doctor Degree Candidate  The National Key Laboratory of Coastal  Offshore Engineering  Dalian University of Technology  Dalian Professor  The National  Key Laboratory of Coastal  Offshore Engineering  Dalian University of Technology  Dalian Associate Professor  The National Key Laboratory of Coastal  Offshore Engineering  Dalian University of Technology  Dalian 《中国海洋工程》1995,(4)

The mild-slope equation derived by Berkhoff (1972), has widely been used in the numerical calculation of refraction and diffraction of regular waves. However, it is well known that the random sea waves has a significant effect in the refraction and diffraction problems. In this paper, a new form of time-dependent mild slope equation for irregular waves was derived with Fade approximation and Kubo's time series concept. The equation was simplified using WKB method, and simple and practical irregular mild slope equation was obtained. Results of numerical calculations are compared with those of laboratory experiments.  相似文献   

Structural Vibration Mode Re-Analysis of Offshore Structures     

Jin Xianding Sun Renzhang Rrofessor  Dept. of Naval Architecture  Ocean Engineering  Shanghai Jiao Tong University  Shanghai Engineer  Applied Software Development Center of China State Shipbuilding Corp 《中国海洋工程》1994,(1)

-This paper reviews the current methodology for dynamic reanalysis. Rayleigh-Ritz approach and receptance approach are discussed in detail. Based on a general finite element structural analysis program SAPS, an eigenproblem re-analysis prorgram ERP was compiled. With a very small change the program can be implemented readily with any general FEM program. Finally, some numerical examples show that the new algorithm is of high precision and efficiency. In the case of local modification in the offshore platform, the efficiency is raised by 20- 50 times when compared with the re-calculation of the whole model.  相似文献   

Design Curves for Mooring Lines of Turret Mooring Systems   总被引：1，自引：0，他引：1  

Gao Jie Tan Jiahua Chen Xiaohong Associate Professor  Shanghai Jiao Tong University  Shanghai Professor  Shanghai Jiao Tong University  Shanghai Lecturer  Shanghai Jiao Tong University  Shanghai 《中国海洋工程》1997,(4)

This paper presents a series of design curves to aid in the selection of turret mooring systemsfor tankers based Floating Production Storage and Offloading(FPSO)systems.These curves are appropri-ate to water depths ranging from 100m to 600m.The curves can be used as a preliminary design tool,al-lowing the designer to quickly evaluate alternative mooring system configurations,including the numberof mooring lines,the characteristics of chain and wire rope to be deployed and the initial tension.With aknowledge of the total environmental force and vessel motion characteristics,the designer can determinethe appropriate system for closer evaluation.  相似文献   

Groupiness of Sea Waves and Their Characteristic Parameters   总被引：1，自引：0，他引：1  

Yu Yuxiu Gui Manhai Professor  Dept. of Civil Eng. Dalian University of Technology  Dalian Master  Dept. of Civil Eng. Dalian University of Technology  Dalian 《中国海洋工程》1996,(1)

Three methods for studying wave groups and their main parameters for describing wave groupiness are reviewed in this paper. Then they are analyzed and compared combined with field data from both aspects of group height and group length. A method and two parameters that can describe wave groupiness are suggested. The groupiness parameters of sea waves at three field stations are given. The effects of groupiness on both distributions of the wave height and the phase of component waves are investigated. The effects of datum length on the calculated value of grouping parameters are also discussed.  相似文献   

New Method for Predicting the Motion Responses of A Flexible Joint Multi-Body Floating System to Irregular Waves   总被引：4，自引：0，他引：4  

CHEN  Xujun 《中国海洋工程》2001,(4):491-498

A new hybrid method of frequency domain and time domain is developed in this paper to predict the motion responses of a flexibly joint multi-body floating system to irregular waves. The main idea of the method is that the three-dimensional frequency method is used to obtain the hydrodynamic coefficients and the response equations are solved in time domain step by step. All the forces can be obtained at the same time. The motions and nonlinear mooring forces of a box type six-body floating system are predicted. A comparison of the theoretical method-based solutions with experimental results has shown good agreement.  相似文献   

Torsionally Coupled Response Control of Offshore Platform Structures Using Circular Tuned Liquid Column Dampers     

霍林生  李宏男 《中国海洋工程》2004,18(2):173-183

In this paper, the control performance is investigated of Circular Tuned Liquid Column Dampers (CTLCD) over torsional response of offshore platform structures excited by ground motions. Based on the equation of motion for the CTLCD-structure system, the optimal control parameters of CTLCD are given through some derivations on the supposition that the ground motion is a stochastic process. The influence of systematic parameters on the equivalent damping ratio of the structures is analyzed with purely torsional vibration and translational-torsional coupled vibration, respectively, The results show that the Circular Tuned Liquid Column Damper (CTLCD) is an effective torsional response control device.  相似文献