柱对称双浮子波能装置散射问题的解析方法     

吴必军  郑永红  游亚戈  孙晓燕  陈勇 《海洋学报》2004,26(3):115-125

通过构造绕射势特解的一种新表达式,基于特征函数展开法提出了线性入射波作用下柱对称双振荡浮子波能装置散射问题的一种新的表达式,并在此基础上计算了垂向波浪激励力.从速度势的求解过程可知,绕射势和辐射势的计算量相当,但垂向波浪激励力的计算比采用Haskind关系方法简单得多,两种方法的结果一样.另外对不同工况下垂向波浪激励力的变化趋势进行了分析.  相似文献   

Model tests on performance of offshore wind turbine with suction caisson foundation in sand     

Hai-lei Kou  Dan-liang Yang  Wang-chun Zhang  Yi-fan Wu  Qiang Fu 《Marine Georesources & Geotechnology》2020,38(8):980-988

Abstract

The performance of steel caisson during and after installation with different penetration velocities in medium dense sand is presented. The applied jacking forces, the amount of formed soil heave and bearing capacity were measured in the model tests. The influence of penetration velocities on jacking forces, soil heave and bearing capacity were also discussed in detail. The results indicated that the jacking forces for caisson in medium dense sands were significantly affected by the penetration velocity. The larger the penetration velocity, the more soil flowed into the caisson cavity during installation. This will lead to larger inner shaft resistance and in turn more jacking forces required for the same penetration depth. The height of soil heave during installation increases with penetration velocity. The m value calculated by the ratio of the volumes of the soil heave to that of the penetrated caisson wall can be used to evaluate the soil heave. The larger the applied velocity, the larger the m value and larger bearing capacity of caisson after installation. The relationship between the m value and penetration velocity can be used to control the soil heave for a steel caisson with a wall thickness to external diameter ratio of 4.2% in medium dense sand by jacking method.  相似文献   

状态空间模型在海洋波能转换系统中的应用 Ⅱ.单个矩形振荡浮子装置运动受力分析的解析方法     

郑永红  游亚戈  沈永明  吴必军  刘荣 《海洋学报》2004,26(1):113-124

对线性入射波作用下的矩形振荡浮子运动受力分析给出了一种新的解析方法.对该方法首先采用特征函数展开法得到绕射速度势的一种新解析式,然后直接由绕射势和入射势来计算波浪激励力.与经典方法相比可以看出,对于立面二维问题,由于绕射势和辐射势的计算量相当,因此该方法比过去常用的解析法更为简单.为了验证方法的正确性,采用该方法对过去文献介绍的经典算例进行了计算,得到了与过去方法完全一致的结果,从而证明该方法是正确的.  相似文献   

A Study on the Maneuvering Motion of a Low Speed Submersible     

Huang Guoliang Liu Tianwei Yan Naichang Associate Professor  Shanghai Jiao Tong University  Shanghai Engineer  Shanghai Jiao Tong University  Shanghai . Professor  Shanghai Jiao Tong University  Shanghai 《中国海洋工程》1997,(4)

In this paper,the maneuvering characteristics of a low speed submersible are investigated.First,the captive model tests are carried out to obtain the hydrodynamic forces acting on the submersibleusing a Planar Motion Mechanism(PMM).For the hydrodynamic forces within a wide range of attack an-gles,the hydrodynamic coefficients which are usually used in the conventional maneuvering motion arequite difficult to be applied.In this case,a Fourier series is adopted to represent the hydrodynamic forcesand it fits the experimental data well.Then,based on the experimental results the simulation calculationsare made to predict some of the maneuvering performance of the low speed submersible.  相似文献   

消除"不规则频率"的非连续高阶元方法   总被引：2，自引：0，他引：2  

孙亮 滕斌张晓兔  何广华 《海洋工程》2004,22(4):51-59

针对使用边界元法计算波浪与结构物相互作用时所出现的“不规则频率”现象，采用连续高阶元和部分非连续高阶元对通过修改积分区域所获得的边界积分方程进行离散，有效地消除了“不规则频率”现象的发生。波浪作用下的截断圆柱所受到的水平波浪力和垂向波浪力的数值计算结果验证了该方法的有效性，同时考虑了非连续单元配置点的选择及单元划分数目对消除效果的影响。  相似文献   

Wave-Current Forces on Small Square Cylinders (Part II)     

Li Yucheng  He Ming Professor 《中国海洋工程》1994,(4)

Based on model tests, the lift and resultant forces on small square cylinders caused by waves (regular and irregular) and currents are analyzed in this paper. The lift and resultant force coefficients CL and Cf related to KC number and the effect of direction of wave propagation are also given, which may be useful for practical engineering application.  相似文献   

Investigation of Motion of Two Hinged Bodies Moored by Mooring Lines in Waves     

JI  Hengteng 《中国海洋工程》2002,16(2):193-200

In this paper, the motions are studied of a multi-body which is composed of two plates hinged together and moored by eight mooring lines in regular waves. The experimental results are compared with computational results. The linear po-tential theory and the perturbation method are combined to study this complicated system. The former is used to calculate the wave forces acting on the plates and the motion responses of them, while the latter is used to describe the dynamic character of the eight mooring lines coupled with the two hinged plates. Some response results of each plate are presented and comparisons between calculated results and experimental data are given. All the calculations are confined to regular beam waves.  相似文献   

Nonlinear heave radiation forces on two-dimensional single and twin hulls     

Sangita Maiti  Debabrata Sen   《Ocean Engineering》2001,28(8):662

A study of nonlinear heave radiation of two-dimensional single and double hulls has been carried out in the time domain. The problem is analyzed by means of a fully nonlinear mathematical model, referred to as the mixed Eulerian–Lagrangian (MEL) model, which is based on an integral relation formulation coupled with time-integration of the nonlinear free-surface boundary conditions. The integral equation solver is based on a cubic-spline boundary-element scheme in which both potential and velocity continuity conditions can be enforced through the intersection points. The body undergoes periodic forced heave oscillation. By implementing effective wave-absorbing beaches at the two ends of the rectangular numerical tank, long-term steady-state force-histories could be achieved consistently in all computations.Results in terms of radiation forces for rectangular and triangular single- and twin-hull geometries are presented and discussed. Linear hydrodynamic forces in terms of added-mass and damping are validated for the rectangular hull. The Fourier-analyzed results reveal the extent of nonlinear (higher-order) components in the force-signals over different parameters which include the amplitudes of oscillation, hull-spacing for the twin-hulls and water depth.  相似文献   

改进波浪发电浮标性能的试验研究   总被引：1，自引：1，他引：1  

黄国樑  冯伯俊  刘天威  龚骅  张文虎 《海洋工程》1994,(1)

为了改进波浪发电浮标为性能，以及推广使用，使之能适用于波浪周期短波高小的海区，对上海航标厂的波浪发电浮标为浮体进行了试验研究。试验测量了气室压力、内波高、浮体升沉等物理量。通过输出功率的比较，提出了浮体设计方案的建议。  相似文献   

Wave force on vertically submerged circular thin plate in shallow water     

Pradip Deb Roy  Sukamal Ghosh   《Ocean Engineering》2006,33(14-15):1935-1953

The paper presented is a solution of shallow water wave force, using small amplitude linear wave theory on two-dimensional vertically submerged circular thin plates under three different configurations: (1) a surface-piercing circular thin plate, (2) a submerged circular thin plate, and (3) a bottom-standing circular thin plate. Finally Morison's equation is used for the determination of wave force which is based on the linear wave theory. The plate is submerged in water near the shore on uniformly sloping bottom. The solution method is confined in a finite domain, which contains both the region of different depth of water and the plate. Laplace's equation and boundary value problems are solved in a finite domain, by the method of separation of variables and the small amplitude linear wave theory. The variation of horizontal force by single particle, total horizontal force and moment with respect to the wave amplitude are obtained at different depth of water and at different wave period. It is observed that the force and moment are converging with the increase of wave period and the gradients of force and moment with respect to the wave amplitude are extremely high for lower wave period.  相似文献