Application of VOF in Calculating Wave Energy Loss due to Spilling Breaker     

Dong Guohai  Li Yucheng Wang Yongxue Lecturer  Doctor  Dalian University of Technology  Dalian Professor  Dalian University of Technology  Dalian 《中国海洋工程》1995,(1)

- A large amount of experimental analysis and systematical theoretical calculation has been done by the authors to solve the problem of wave transformation and breaking, considering the effect of both current and topography, but only the wave energy loss due to spilling breaker in the surf zone has been discussed in this paper. Based on test result analysis and calculation with the Stream Function Wave Theory, the wave velocity field at breaking points has been obtained, and it is used to calculate the wave heights after breaking by the VOF (Volume of Fluid) method, in which the governing equations are continuity equation and Navier-Stokes Equation for imcompressible fluids. In the present paper, the improved VOF technique is used to calculate the wave heights of stable regular waves after breaking. Results fit the test data well, which shows that the VOF method is suitable to numerical simulation of regular waves after breaking. Besides, the breaker coefficient B of regular waves in the bore model is a  相似文献   

Application of DDA Approach to Simulation of Ice Breaking Process and Evaluation of Ice Force Acting on A Structure     

ZHANG  Yunliang 《中国海洋工程》2002,16(3):273-282

The sea ice is idealized as an elastic-brittle material. When an ice sheet moves toward a structure, the dynamic in-teraction between ice and the structure is analyzed by the DDA (Discontinuous Deformation Analysis) approach, where the ice sheet and the structure are considered as assemblages of blocky masses. This has the advantages that the whole process of collision between the ice and structure can be shown visually vvith a series of pictures. Meanwhile, the dynamic response of the structure at each time step after the bumping of the ice against the structure is calculated. And with the aid of inverse analysis developed by the authors, the time history of the resultant ice force exerting on the structure is evaluated. A numerical example shows that the proposed approach is suitable to the simulation of the ice-breaking process and reasonable result of ice force acting on the structure can be obtained.  相似文献   

The application of Hartley transform to ocean engineering   总被引：1，自引：0，他引：1  

Hequan Sun  Dahong Qiu  Yongxue Wang 《海洋学报(英文版)》2003,22(3):483-490

The Hartley transform is a real integral transform based on harmonic functions and hassome characteristics similar to the Fourier transform. Most applications in ocean engineering requiring the Fourier transform can also be performed by the Hartley transform. The fast Hartley transform is twice faster and more convenient to handle than the corresponding fast Fourier transform, so it is a real valued alternative to the complex Fourier transform in many applications. The use of the Hartley transform in ocean engineering is presented in detail in this paper, including wave spectral analysis, separation of waves, cross-correlation in PIV technique and expression of equation in the Hartley domain. The examples in the paper show deeply the advantage and efficiency of the Hartley transform over the Fourier transform.  相似文献   

波流共同作用下海底子母管线水动力的物理模型试验研究     

成小飞  王永学  王国玉 《海洋学报》2012,34(4):172-180

通过物理模型试验研究海底子母管线分别在规则波加流和不规则波加流作用下的水动力特性。基于Morison方程,采用"等效直径法"分析得到子母管线拖曳力系数C_D,惯性力系数C_M和升力系数C_L(C_D+,C_L-)。试验分别考察了流速比U_c/U_w,母管与海床间隙比e/D及子母管间的相对缝隙G/D对海底子母管线水动力系数的影响。结果表明水动力系数随U_c/U_w的增大而减小;当e/D<0.5时,海床对子母管线受力的影响比较明显,C_D,C_M及C_L+均随e/D增大而减小,|C_L-|随e/D增大而增大;对子母管间的相互影响也不可忽略,C_D,C_M和|C_L-|均随G/D增大而减小,C_L+值随G/D增大而增大。  相似文献   

波浪对透空式结构物冲击作用的光滑粒子流体动力学数值模拟   总被引：3，自引：0，他引：3  

任冰  高睿  金钊  王国玉  王永学 《海洋学报》2012,34(1):163-177

基于光滑粒子流体动力学(SPH)方法的二维数值波浪水槽模拟了规则波对透空式结构物的冲击作用。通过黎曼解和CSPM相结合的方法对连续方程和动量方程进行了修正。对造波边界采用虚粒子法模拟。提出了一种耦合计算方法来消除造波边界附近的压力波动现象,在结构物边界处设置了适合的冲击边界条件。应用修正的SPH模型模拟了规则波对浪溅区结构物的冲击作用,给出了结构物附近流场和压力场的变化特征,并应用物理模型试验结果对数值模型进行了验证。  相似文献   

Numerical Model of Cnoidal Wave Flume     

WANG Yongxue  ZANG Jun QIU Dahong Professor  the State Key Laboratory of Coastal  Offshore Engineering  Dalian University of Technology  Dalian  P. R. China Lecturer  the State Key Laboratory of Coastal  Offshore Engineering  Dalian University of Technology  Dalian  P. R. China Professor  Academician of Chinese Academy of Sciences  the State Key Laboratory of Coastal  Offshore Engineering  Dalian University of Technology  Dalian  P. R. China 《中国海洋工程》1999,(4)

The volume of fluid(VOF)method is used to set up a wave flume with an absorbing wavemaker of cnoidal waves.Based on the transfer function between wave surface and paddle velocity obtained bythe shallow water wave theory,the velocity boundary condition of an absorbing wave maker is introduced toabsorb reflected waves that reach the numerical wave maker.For H/d ranging from 0.1 to 0.59 and T(g/d)~(1/2)from 7.9 to 18.3,the parametric studies have been carried out and compared with experiments.  相似文献   

南海历史地理争端空间分布与关联性研究     

邹伟  刘永学  李满春  张荷霞  陈映雪 《地球信息科学学报》2014,16(2):249-256

南海占我国海洋国土的2/3,不仅是中国国家安全的天然屏障和重要的出海口与战略通道,而且是我国未来重要的能源接续区与资源基地、地缘政治经济问题的多发区。对南海争端发展态势进行空间分布与关联性GIS分析,是重要的辅助决策支持。结果表明：（1）文献研究和网络爬虫等方法可以快速有效地获取南海争端历史地理数据,GIS技术能够对南海争端历史地理数据进行时空变化的深入分析;（2）就争端事件的时间分布而言,事件数量随时间推进呈现显著增长,个别发生重大南海争端事件的年份出现突增的现象;（3）就争端事件的空间分布而言,与越南及菲律宾相关的南海争端事件尤甚,其他周边国家则相对较少,这主要源于越菲两国的战略利益与南海所在区域交叠,使得越菲不断挑起事端;（4）越南、菲律宾与马来西亚等国的利益诉求区主要位于南沙群岛,各国诉求区分布明确,局部交错。网络GIS技术丰富了历史地理研究的途径,为其提供了新的思路和方法。  相似文献   

非线性波浪时域计算的三维耦合模型   总被引：3，自引：1，他引：2  

齐鹏  王永学  邹志利  邱大洪 《海洋学报》2000,22(6):102-109

将计算区域Ω划分为内域Ω₁和外域Ω₂(Ω₂=Ω-Ω₁),外域控制方程采用改进线性频散特性的二维Boussinesq方程,用预报一校正法数值求解;结构物附近的内域控制方程为三维Navier-Stokes方程,由VOF方法数值求解。通过在外域和内域相匹配的交界面上设置合适的速度和波面边界条件,建立了三维非线性波浪时域计算的耦合模型。模拟试验表明:(1)耦合模型数值波浪水池可以产生稳定的、重复性较好的波动过程;(2)用耦合模型数值波浪水池求解较大浅水区域上的非线性波浪数值计算问题可以取得较高的计算效率,同时又能得出结构物附近的复杂流场。  相似文献   

基于主客观权重集成法的OWC装置波能转换效率评价          下载免费PDF全文

马晨哲  王永学  陈静 《海洋开发与管理》2019,36(12):61-66

OWC装置的结构形式繁多,共振周期也各不相同,全面合理地评价OWC装置的工作性能具有重要的现实意义。为优化OWC装置的工程选型,文章基于主客观权重集成法,分别采用层次分析法和熵值法计算峰值波能转换效率、一级衰减和二级衰减3个指标的主观权值和客观权值,并通过优化模型进行组合,从而确定综合权值;利用3个指标的综合权值,对4种不同结构的OWC装置的平均波能转换效率进行评分,并对评分结果进行验证和分析。研究结果表明:在所选的4种装置结构中,圆截面U-OWC的评分最高,即具有最高的平均波能转换效率;与传统OWC结构相比,U-OWC结构的平均波能转换效率较高,在实际工程中有更好的表现,在满足条件时宜优先采用。  相似文献   

海岸带水体遥感信息全自动提取方法   总被引：1，自引：0，他引：1  

江冲亚  李满春  刘永学 《测绘学报》2011,40(3):332-337

在对经典的水体遥感信息提取方法分析的基础上,针对海岸带水体的特点了提出一种新的方法,该方法通过“像元-对象”及“全域-局部”的双重尺度转换,综合利用了海岸带水体遥感信息的光谱特征、空间特征、统计特征和不确定性,有机结合了地学知识与数据挖掘方法,实现了海岸带水体遥感信息的全自动提取。对我国四大海域不同类型海岸带的Landsat ETM+遥感影像进行试验,发现应用该方法能够兼顾宏观和微观的水体特征,提取结果具有较好的完整性和连续型,相对精度优于监督分类法和阈值分割法。  相似文献