A finite element model of interaction between viscous free surface waves and submerged cylinders     

Gang Zhu  Alistair G. L. Borthwick  Rodney Eatock Taylor 《Ocean Engineering》2001,28(8)

This paper describes the simulation of the flow of a viscous incompressible Newtonian liquid with a free surface. The Navier–Stokes equations are formulated using a streamline upwind Petrov–Galerkin scheme, and solved on a Q-tree-based finite element mesh that adapts to the moving free surface of the liquid. Special attention is given to fitting the mesh correctly to the free surface and solid wall boundaries. Fully non-linear free surface boundary conditions are implemented. Test cases include sloshing free surface motions in a rectangular tank and progressive waves over submerged cylinders.  相似文献   

Modified mild slope equation and open boundary conditions     

M. C. Khellaf  M. Bouhadef 《Ocean Engineering》2004,31(13):1713-1723

A numerical model to compute wave field is developed. It is based on the Berkhoff diffraction-refraction equation, in which an energy dissipation term is added, to take into account the breaking and the bottom friction phenomena. The energy dissipation function, by breaking and by bottom friction, is introduced in the Berkhoff equation to obtain a new equation of propagation.The resolution is done with the hybrid finite element method, where lagrangians elements are used.  相似文献   

Stress and deformation of offshore piles under structural and wave loading   总被引：3，自引：0，他引：3  

J. A. Eicher  H. Guan  D. S. Jeng   《Ocean Engineering》2003,30(3):369-385

Various offshore structures, especially large structures such as Tension Leg Platforms (TLP), are usually supported by concrete piles as the foundation elements. The stress distribution within such a large structure is a dominant factor in the design procedure of an offshore pile. To provide a more accurate and effective design for offshore foundation systems under axial and lateral wave loads, a finite element model is employed herein to determine the stresses and displacements in a concrete pile under similar loading conditions. A parametric study is also performed to examine the effects of the stress distribution due to the changing loading conditions.  相似文献   

海泥环境中阴极保护的边界元计算     

王秀通  侯保荣  李焰 《海洋科学》2006,30(12):62-64

根据阴极保护的特点,建立了用于数值计算的模型;采用边界元方法对海泥介质中的阴极保护系统进行了计算,获得了海泥中钢管表面以及海泥介质内部的电位分布。将计算的结果与测量的数据进行比较,两者具有较好的一致性。  相似文献   

Second-Order Wave Diffraction Around 3-D Bodies by A Time-Domain Method   总被引：1，自引：1，他引：1  

BAI  Wei 《中国海洋工程》2001,(1):73-84

A time-domain method is applied to simulate nonlinear wave diffraction around a surface piercing 3-D arbitrary body. The method involves the application of Taylor series expansions and the use of perturbation procedure to establish the corresponding boundary value problems with respect to a time-independent fluid domain. A boundary element method based on B-spline expansion is used to calculate the wave field at each time step, and the free surface boundary condition is satisfied to the second order of wave steepness by a numerical integration in time. An artificial damping layer is adopted on the free surface for the removal of wave reflection from the outer boundary. As an illustration, the method is used to compute the second-order wave forces and run-up on a surface-piercing circular cylinder. The present method is found to be accurate, computationally efficient, and numerically stable.  相似文献   

Boussinesq-type modelling using an unstructured finite element technique     

Ole R. Srensen  Hemming A. Schffer  Lars S. Srensen 《Coastal Engineering》2004,50(4):181-198

A model for solving the two-dimensional enhanced Boussinesq equations is presented. The model equations are discretised in space using an unstructured finite element technique. The standard Galerkin method with mixed interpolation is applied. The time discretisation is performed using an explicit three-step Taylor–Galerkin method. The model is extended to the surf and swash zone by inclusion of wave breaking and a moving boundary at the shoreline. Breaking is treated by an existing surface roller model, but a new procedure for the detection of the roller thickness is devised. The model is verified using four test cases and the results are compared with experimental data and results from an existing finite difference Boussinesq model.  相似文献   

海水中A3钢样阴极保护电化学场的二维有限元计算     

王在峰  孙虎元  孙立娟 《海洋科学》2006,30(7):38-42

有限元法已被证明是计算阴极保护场中电位、电流密度分布的有效方法。作者建立了二维的有限元数学模型,并讨论了模型中电化学场的非线性边界条件的处理和非线性方程组的迭代法解法。用构建的模型对简单的阴极保护模拟体系进行了分析,得出了较合理的结果。  相似文献   

Third order contribution to the wave-making resistance of a ship at finite depth of water     

Shahjada Tarafder  Md 《Ocean Engineering》2007,34(1):32-44

This paper presents a potential based boundary element method for solving a nonlinear free surface flow problem for a ship moving with a uniform speed in finite depth of water. The free surface boundary condition is linearized by the systematic method of perturbation in terms of a small parameter up to third order. The surfaces are discretized into flat quadrilateral elements and the influence coefficients are calculated by Morino's analytical formula. Dawson's upstream finite difference operator is used in order to satisfy the radiation condition. The second order solution gives better result than the first or third order solution. So the present method with the second order solution can be adopted as a powerful tool for the hydrodynamic analysis of the thin ship in finite depth of water.  相似文献   

复合加载条件下吸力式沉箱基础承载特性数值分析   总被引：2，自引：0，他引：2  

王志云  王栋  栾茂田  范庆来  武科 《海洋工程》2007,25(2):52-56,71

吸力式沉箱基础的承载特性是海洋工程结构设施建造与设计中的一个关键问题。这种新型的深水海洋基础型式,通常承受竖向上拔荷载与水平荷载的共同作用,其工作性能与设计理论远远不能满足工程实践的需要。本文采用有限元分析方法对吸力式沉箱基础的极限承载特性进行数值计算。以大型通用有限元分析软件ABAQUS为平台,通过二次开发,数值实现了Swipe试验加载方法和固定位移比分析方法,针对不同的沉箱长径比、土的强度折减系数,探讨了沉箱基础在垂直上拔荷载和水平荷载单调联合作用下的极限承载力,通过对不同荷载组合的数值计算构造了复合加载条件下沉箱基础破坏包络面。  相似文献   

自升式平台冰激动力响应分析     

张剑波 《海洋科学进展》2007,25(1):85-90

应用ANSYS软件建立了平台和冰相互作用的有限元模型,构建了自升式平台的冰激振动模型,并计算基于2种冰力模型的自升式平台的动力响应。此动力分析方法具有建模方便和计算精度高的特点。以某自升式平台为例,计算了冰和平台结构相互作用的耦合效应,为自升式平台冰激振动安全评估提供了参考依据。  相似文献