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1.
三维问题中二阶波浪力理论计算的注记   总被引:2,自引:1,他引:1  
一、引言 船舶和海洋工程结构物在波浪中的受力和运动是人们最感兴趣的研究领域之一。许多观察表明,当船舶或海洋工程结构物锚泊在波浪中时,如果波浪是单一频率的规则波,则物体除了产生与波浪频率一致的摇荡运动外,它的平均位置产生漂移;如果波浪是不规则的,还伴之有长周期的摇荡运动,这一运动的频率远低于不规则波的特征频率。这些现象说明,在物体上必然作用有定常的或缓变的波浪漂移力。  相似文献   

2.
大尺度柱状结构物波流荷载研究   总被引:1,自引:0,他引:1       下载免费PDF全文
大型深水工程往往面临水深、浪大以及流急等复杂自然条件,将受到巨大的水平波流力,在工程设计中需准确考虑波流力的大小.通过在波流水槽进行圆柱、方柱和矩形柱波流力系列试验,进行大尺度柱状结构物波流荷载研究,同时建立数学模型,应用边界元法求解大尺度柱体上的波浪荷载,编写了Fortran程序计算波浪力,运用柱体绕流理论计算水流力.对比分析试验结果和数值计算结果提出了波流力工程计算方法:对于深水大尺度柱状结构物波流力可由波浪力线性迭加水流力再乘以1.04得到,计算中波浪要素采用水流影响下的要素,水流力采用柱体绕流求得.按此方法计算波流力,并与物理模型试验结果进行对比,两者误差较小,满足工程设计的精度要求.  相似文献   

3.
针对计算域中存在直立岛式结构物的复连通区域,基于时间关联型缓坡方程和相应的边界条件,建立了在计算域中存在直立岛式结构物时波浪传播的数值模拟模型.该模型不仅适用于变水深问题,而且适用于模拟线性波浪的时间和空间演化过程.对直立岛式防波堤及直立方柱周围波浪传播变形的数值模拟表明,所建立的模型能够有效地模拟计算域内存在直立岛式结构物的波浪绕射和反射问题.  相似文献   

4.
局部开孔防波堤对斜向波反射的理论分析和试验研究   总被引:3,自引:1,他引:2  
李玉成  刘洪杰  董国海 《水利学报》2004,35(10):0063-0070
本文通过理论分析和试验研究相结合的方法,探讨了斜向规则波与局部开孔防波堤的相互作用。流体运动的计算域被分成两个子域,一个区位于开孔沉箱结构物外侧,另一个区位于结构物内。在每个子区域内,应用分离变量法和特征函数展开法以求得相应的速度势,在速度势的特征展开中考虑了非传播模态波。理论计算与试验结果对比表明,二者符合较好。基于对不同因素影响的分析,给出了斜向规则波在局部开孔结构前反射率的简化计算公式,在工程设计中可用于预估类似条件下结构物前的波浪反射率。  相似文献   

5.
波浪增阻是计算船舶能效指标中气象因子w_f的关键。该文基于二维半理论(又称高速细长体理论)实现了船舶运动响应预报并采用辐射能量法开发了波阻增加计算程序。通过对不同航速下Wigley III和S175船的水动力、运动和波浪增阻的细致计算与分析,并与切片理论和三维航速修正法求解的结果及试验值进行了比较,验证该方法的可靠性和适用性。研究表明二维半理论适用于船舶运动与波浪增阻的计算,相较于工程上常用的切片理论和航速修正方法,计算结果准确性适用性更高,为船舶波阻增加预报提供了快速有效的手段。  相似文献   

6.
计算域中存在直立岛式结构物时波浪传播的数值模拟   总被引:3,自引:1,他引:2  
针对计算域中存在直立岛式结构物的复连通区域,提出了岛体边界条件,利用缓坡方程建立了在计算域中存在直立岛式结构物时波浪传播的数值模拟模型。模型适用于变水深水域问题,克服了解析解只能适用于等水深水域的不足。直立圆柱和无穷小厚度岛式防波堤周围波浪传播的数值算例表明,数值解与解析解吻合良好,说明所建立的数值模拟模型能有效地模拟复连通区域内的波浪传播。矩形固定式防波堤周围波浪场的数值模拟说明该模型对工程实际有较强的适应性。  相似文献   

7.
用三维时变雷诺方程模型模拟小尺度组合桩柱上的波浪力   总被引:2,自引:0,他引:2  
该文以雷诺时均的Navier-Stokes方程为控制方程,用k-ε模型来封闭湍流模型,采用VOF方法来跟踪波动自由表面,建立了三维数学模型。然后对波浪与小尺度孤立柱的相互作用过程进行了数值模拟,得到了时变的波浪力,然后用实验资料进行了验证,并且和Morison方程的计算结果进行了比对。然后利用验证过的模型模拟了三维波浪场中两个不同间距的纵向排列的小尺度桩柱上所受的波浪力,得到了两个桩柱的干扰系数和间距的关系。计算方法和计算结果对此类结构物的设计施工有一定的参考价值。  相似文献   

8.
波浪冲击过程的湍流数值模拟   总被引:27,自引:5,他引:22  
本文通过无反射数值波浪水槽研究了周期波浪对浪溅区结构物的冲击作用,控制方程为雷诺时均方程,采用k-ε紊流模型及在近壁区应用壁函数。建立了适合VOF方法的水体与结构物接触与分离的数值边界条件及动量方程的对流项采用了三阶迎风差分格式以消除数值粘性的影响。通过数模得到了波浪对位于浪溅区结构物底面的波浪冲击压力幅值及沿底面分布的定量结果,讨论了不同结构物尺度及距静水面高度对冲击压力沿建筑物底面分布的影响,  相似文献   

9.
基于势流理论,利用边界元方法,对水下爆炸兴波及其对结构物作用问题进行了数值研究。水下爆炸兴波是基于简单气泡模型的假定,运用满足自由水面条件的时域格林函数进行数值模拟。在时域内分析了水下爆炸兴起的水波对结构物的作用,并初步探讨了波浪力随炸药量、埋深及结构物与炸源水平距离的变化规律,有较好的参考价值。在规则波作用下波浪力的计算结果与频域方法吻合良好,验证了该文数值方法的有效性。  相似文献   

10.
二维甲板上浪问题数值模拟研究的新方法   总被引:1,自引:1,他引:0  
甲板上浪问题一直是强非线性问题研究领域的热点,它是造成海洋浮式结构物损坏的重要因素.该文完整的阐述了用于研究甲板上浪问题的数值模拟解决方案,并对二维浮动物体的运动响应、甲板上浪进行了考察.模拟在二维数值波浪水池中完成,入射波由冲箱运动生成,水池远端采用海绵层吸收反射波浪,自由液面采用VOF方法捕捉,物体的运动为与波浪的耦合运动.最后将模拟得到的运动响应与试验进行了对比,同时对上浪载荷也进行了分析.  相似文献   

11.
简要介绍了Boussinesq方程的形式和特点,参考丹麦Abbott等人提出的改进的该方程的形式及解法,初步建立了考虑底摩擦效应、波浪破碎效应的Boussinesq方程波浪数学模型,将其应用于港池波浪计算,并与海港水文规范的计算结果进行对比分析。  相似文献   

12.
In this paper we propose a new model based on a contravariant integral form of the fully non-linear Boussinesq equations(FNBE) in order to simulate wave transformation phenomena, wave breaking, runup and nearshore currents in computational domains representing the complex morphology of real coastal regions. The above-mentioned contravariant integral form, in which Christoffel symbols are absent, is characterized by the fact that the continuity equation does not include any dispersive term. The Boussinesq equation system is numerically solved by a hybrid finite volume-finite difference scheme. A high-order upwind weighted essentially non-oscillatory(WENO) finite volume scheme that involves an exact Riemann solver is implemented. The wave breaking is represented by discontinuities of the weak solution of the integral form of the non-linear shallow water equations(NSWE). On the basis of the shock-capturing high order WENO scheme a new procedure, for the computation of the structure of the solution of a Riemann problem associated with a wet/dry front, is proposed in order to simulate the run up hydrodynamics in swash zone. The capacity of the proposed model to correctly represent wave propagation, wave breaking, run up and wave induced currents is verified against test cases present in literature. The results obtained are compared with experimental measures, analytical solutions or alternative numerical solutions. The proposed model is applied to a real case regarding the simulation of wave fields and nearshore currents in the coastal region opposite San Mauro Cilento(Italy).  相似文献   

13.
A set of nonlinear Boussinesq equations with fully nonlinearity property is solved numerically in generalized coordinates,to develop a Boussinesq-type wave model in dealing with irregular computation boundaries in complex nearshore regions and to facilitate the grid refinements in simulations.The governing equations expressed in contravariant components of velocity vectors under curvilinear coordinates are derived and a high order finite difference scheme on a staggered grid is employed for the numerical implementation.The developed model is used to simulate nearshore wave propagations under curvilinear coordinates,the numerical results are compared against analytical or experimental data with a good agreement.  相似文献   

14.
多极子去奇异边界元法在三维水波问题中的应用   总被引:1,自引:1,他引:0  
在众多水波问题,尤其是非线性水波问题求解中,巨大计算量和存储量一直是人们试图克服和解决的重点与难点。本文通过对简单Green函数基本解1/r做多极子展开,并应用到去奇异边界元法中求解三维水波问题。通过无限区域中水流对圆球绕射算例的数值计算,验证了多极子去奇异边界元法能给出高精度的满意结果,与传统边界元方法相比避免了边界积分中奇异性的单独处理并将计算量和存储量均降到了O(NIgN)和O(N)数量级,同时对完全非线性水波问题的时域模拟也得出了令人满意的结果,验证了该方法在处理大计算量问题中所具有的优势。  相似文献   

15.
利用有关文献提供的可能最大台风风场,采用文圣常等提出的混合型海浪数值模式计算了厂址外海域可能最大台风浪,再经近岸折绕射计算得出了厂坪关沿设计波要素,并对计算结果做了分析。  相似文献   

16.
The boundary element method(BEM) is a main method for analyzing the interactions between the waves and the marine structures. As with the BEM, a set of linear equations are generated with a full matrix, the required calculations and storage increase rapidly with the increase of the structure scale. Thus, an accelerated method with a low storage is desirable for the wave interaction with a very large structure. A systematic review is given in this paper for the BEM for solving the problem of the wave interaction with a large scale structure. Various integral equations are derived based on different Green functions, the advantages and disadvantages of different discretization schemes of the integral equations by the constant panels, the higher order elements, and the spline functions are discussed. For the higher order element discretization method, the special concerns are given to the numerical calculations of the single-layer potential, the double layer potential and the solid angle coefficients. For a large scale computation problem such as the wave interaction with a very large structure or a large number of bodies, the BEMs with the FMM and p FFT accelerations are discussed, respectively, including the principles of the FMM and the p FFT, and their implementations in various integral equations with different Green functions. Finally, some potential applications of the acceleration methods for problems with large scale computations in the ocean and coastal engineering are introduced.  相似文献   

17.
本文首先开发了基于射线理论的浅水波计算程序,提出了解决射线相交的方法。应用非线性长波方程,以波浪对圆柱体(岛)和海凹的绕、折射以及对坡岸的斜向入射为例进行了计算,其中在变深开边界处利用射线理论结果为给定入射波,获得了与实际观测相吻合的结果。  相似文献   

18.
为了将黏弹性人工边界条件用于成层地基模型的计算中,基于波动理论,推导了不同类型地震波的波幅比计算公式,采用延迟法考虑行波效应,完成了成层地基的自由场求解,得到了考虑地震波一次反射透射的等效荷载计算公式,最终建立了考虑成层地基的黏弹性人工边界模型。以SV波垂直入射为例,采用所建立的模型进行了重力坝的动力计算。结果表明,该模型满足工程抗震分析的精度要求,可以解决成层地基条件下,地震波垂直入射时考虑土-结构相互作用的结构动力分析问题。  相似文献   

19.
NUMERICAL SIMULATION OF EXTREME WAVE GENERATION USING VOF METHOD   总被引:1,自引:0,他引:1  
Numerical simulations of extreme wave generation are carried out by using the Volume Of Fluid (VOF) method. Extreme waves are generated based on wave focusing in a 2-D numerical model. To validate the capability of the VOF-based model described in this article, the propagation of regular waves is computed and compared with the theoretical results. By adjusting the phases of wave components, extreme waves are formed at given time and given position in the computation. The numerical results are compared with theoretical solutions and experimental data. It is concluded that the present model based on the VOF technique can provide acceptably accurate numerical results to serve practical purposes.  相似文献   

20.
URANS simulations of ship motion responses in long-crest irregular waves   总被引:1,自引:0,他引:1  
In this paper, numerical prediction of ship motion responses in long-crest irregular waves by the URANS-VOF method is presented. A white noise spectrum is applied to generate the incoming waves to evaluate the motion responses. The procedure can replace a decade of simulations in regular wave with one single run to obtain a complete curve of linear motion response, considerably reducing computation time. A correction procedure is employed to adjust the wave generation signal based on the wave spectrum and achieves fairly better results in the wave tank. Three ship models with five wave conditions are introduced to validate the method. The computations in this paper are completed by using the solver naoe-FOAM-SJTU, a solver developed for ship and ocean engineering based on the open source code OpenFOAM. The computational motion responses by the irregular wave procedure are compared with the results by regular wave, experiments and strip theory. Transfer functions by irregular wave closely agree with the data obtained in the regular waves, showing negligible difference. The comparison between computational results and experiments also show good agreements. The results better predicted by CFD method than strip theories indicate that this method can compensate for the inaccuracy of the strip theories. The results confirm that the irregular wave procedure is a promising method for the accurate prediction of motion responses with less accuracy loss and higher efficiency compared with the regular wave procedure.  相似文献   

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