Simulation and Analysis of a Gravity Cyh''''nder''''s Stability in Short-Crested Sea     

Yu Ke  Su Weidong Postgraduate  River  Harbour Department  Nanjing Hydraulic ResearchInstitute  Nanjing Engineer  River  Harbour Department  Nanjing Hydraulic Research Institute  Nanjing 《中国海洋工程》1992,(1)

Generally, the reliability of ami -sliding and anti-overturning stability of an isolated gravity cylinder in a certain working period can be evaluated only when the statistical properties of short term stability are given first. The authors used numerical method to simulate the stability state function of a cylinder in short-crested sea, and further to get the probabilitical characteristics of the structure's stability by time domain analysis. The external loads appeared in the state functions include horizontal wave force, lift force and the respective moments, and the loads are correlated by co- spectrum. The numerical method presented in this paper can be used not only to solve short term reliability problem directly, but to calculate and analyse the long term reliability problem as well. For circular cylinders, an example of simulation and analysis is displayed in this paper.  相似文献   

An Analytic-Numerical Solution of Wave Transformation     

Feng Weibing Hong Guangwen Ph. D Student  Hohai University  Nanjing . Professor  Hohai University  Nanjing 《中国海洋工程》1995,(1)

An analytic-numerical solution of wave transformation in shoaling water is presented in this paper. The analytical expression for wave heights along the wave rays is derived in consideration of the combined effect of water depth shoaling, the wave refraction and the sea bottom friction. The wave rays (orthogonals) are calculated by a fourth order Runge-Kutta algorithm and the wave crest lines are computed by an iteration procedure. The numerical results are compared with analytical solution for a special case of parallel- straight contour shore and field data, and comparisons show that the proposed mathematical model and computation method are very useful and convenient for engineering application.  相似文献   

Transformation of Wave Energy Spectrum in Shallow Water     

Xue Hongchao  Su Dehui Xu Fumin Professor  Research Institute of Coastal  Ocean Engineering  Hohai University  Nanjing Doctor  Dept. of Navigation  Ocean Engineering  Hohai University  Nanjing Ph. D. Student  Dept. of Navigation  Ocean Engineering  Hohai University  Nanjing 《中国海洋工程》1995,(3)

- Combined with irregular wave-maker, the growing process of Wave Energy Spectrum in shallow water can be studied in wind wave channel on different water depth conditions, and its transformation characteristics and rules can be obtained.  相似文献   

Experimental Study on Rectangular Floating Breakwaters     

Yao Guoquan Ma Zhixiong Ding Bingcan Prof. Senior Engineer  River  Harbour Department  Nanjing Hydraulic Research Institute  Nanjing Senior Engineer  River  Harbour Department  Nanjing Hydraulic Research Institute  Nanjing Engineer  River  Harbour Department  Nanjing Hydraulic Research Institute  Nanjing 《中国海洋工程》1993,(3)

This paper proposes ten types of improved floating breakwaters for experiment with regular waves, based on the experience in the development and manufacture of existing floating breakwaters both at home and abroad, and on the results of experimental studies on the hydraulic characteristics of several types of floating breakwaters. The wave heights before and behind the breakwaters are measured, the movements of floating breakwaters are observed and the chain forces of the floating breakwaters are measured. The paper studies and compares the hydraulic characteristics of the improved rectangular floating breakwaters of which the internal and external structures and their installation methods are changed. Finally the optimal type of structure is selected through experiments.  相似文献   

A 2D Mathematical Model for Sediment Transport by Waves and Tidal Currents   总被引：12，自引：5，他引：12  

陆永军左利钦  邵学军王红川 李浩麟 《中国海洋工程》2005,19(4):571-586

In this study, the combined actions of waves and tidal currents in estuarine and coastal areas are considered and a 2D mathematical model for sediment transport by waves and tidal currents has been established in orthogonal curvilinear coordinates. Non-equilibrium transport equations of suspended load and bed load are used in the model. The concept of background concentration is introduced, and the formula of sediment transport capacity of tidal currents for the Oujiang River estuary is obtained. The Dou Guoren formula is employed for the sediment transport capacity of waves. Sediment transport capacity in the form of mud and the intensity of back silting are calculated by use of Luo Zaosen＇ s formula. The calculated tidal stages are in good agreement with the field data, and the calculated velocities and flow directions of 46 vertical lines for 8 cross sections are also in good agreement with the measured data. On such a basis, simulations of back silting after excavation of the waterway with a sand bar under complicated boundary conditions in the navigation channel induced by suspended load, bed load and mud by waves and tidal currents are discussed.  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   

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   

Discharge Control on Boundary of Tidal Models and Measuring Techniques of Low Current Velocity     

Li Guochen Xu Jinhuan Associate Prof.  Dept. of Navigation  Ocean Eng.  Hohai University  Nanjing Lecturer  Dept. of Navigation  Ocean Eng.  Hohai University  Nanjing 《中国海洋工程》1992,(3)

This paper describes the discharge control technique on boundary used in two models, one is the model of hot water drainning in Dayawan Nyclear Power Plant, Guangdong, and the other is the model for trainhing the sand bar at the Guanhe Estuary, Jiangsu. Many years of application shows that this technique has the advantages of good reliability, repeatability and validity. The speedometer of hydrogen bubble is also introduced in this paper. The device can display and store tracing lines in a computer, and help operators to obtain the value and direction of transient velocity of a nonsteady current, thus, the problem of measurment of low current velocity in tidal model tests is solved and the automation of the measurement of current velocity is realized.  相似文献   

Modulus of Subgrade Reaction for Laterally Loaded Piles in Multiple Layered Foundation   总被引：1，自引：1，他引：1  

Lu Ziai Associate Professor  Dept. of Navigation  Ocean Engineering  Hohai University  Nanjing 《中国海洋工程》1997,(4)

-According to the field test data of laterally loaded steel piles at home and abroad,an empiri-cal formula for evaluating the modulus of subgrade reaction under static load in layered soil is proposed.The suggested formula takes account of not only non-linearity of K_s with the depth but also its variationwith the load.It is shown that the computed bending moments along the pile shaft and the deflection atthe pile top are consistent with the measured ones.  相似文献   

Silting in the Lower Courses of Tidal Sluices in China   总被引：2，自引：0，他引：2  

张金善  黄建维杨红 《中国海洋工程》2004,18(1):137-148

Serious sediment deposition often occurs after the construction of tidal sluices in snrall or medium-sized tidal muddy estuaries, so desilting or dredging is needed to meet the demands of flood diseharge, saltwater retaining, and navigation in those areas. In this paper, the problem of sediment deposition induced by construction of tidal sluices is analyzed.Different problems of silting near tidal sluices for different types of estuaries are summed up. at the same time, corresponding methods are given to solve these probleras, and a few successful examples are also given. The idea of comprehensive regulation and utilization of estuaries is put forward, and some proposals for solution of sediment deposition in this kind of estuaries are made.  相似文献