共查询到13条相似文献,搜索用时 15 毫秒
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Nicholas DODD 《中国海洋工程》1999,(2)
-A nonlinear model of mean free surface of waves or wave set-up is presented.The model isbased on that of Roelvink(1993),but the numerical techniques used in the solution are based on theWeighted-Average Flux(WAF)method(Watson et al,1992),with Time-Operator-Splitting(TOS)usedfor the treatment of the source terms.This method allows a small number of computational points to beused,and is particularly efficient in modeling wave set-up.The short wave(or primary wave)energy equa-tion is solved by use of a more traditional Lax-Wendroff technique.A nonlinear wave theory(James,1974)is introduced.The model described in this paper is found to be satisfactory in most respects whencompared with the measurements conducted by Stive(1983)except in modeling the mean free surface veryclose to the mean shoreline. 相似文献
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Based on the Stokes wave theory, the capillary-gravity wave and the interfacial internal wave in two-layer constant depth''s fluid system are investigated. The fluids are assumed to be incompressible, inviscid and irrotational. The third-order Stokes wave solutions are given by using a perturbation method. The results indicate that the third-order solutions depend on the surface tension, the density and the depth of each layer. As expected, the first-order solutions are the linear theoretical results (the small amplitude wave theoretical results). The second-order and the third-order solutions describe the nonlinear modification and the nonlinear interactions. The nonlinear impact appears not only in the n (n≥2) times'' high frequency components, but also in the low frequency components. It is also noted that the wave velocity depends on the wave number, depth, wave amplitude and surface tension. 相似文献
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LI Yucheng 《中国海洋工程》2000,14(1):59-67
—An experimental study of regular wave and irregular wave breaking is performed on a gentleslope of 1:200.In the experiment,asymmetry of wave profile is analyzed to determine its effect on wavebreaker indices and to explain the difference between Goda and Nelson about the breaker indices of regu-lar waves on very mild slopes.The study shows that the breaker index of irregular waves is under less influ-ence of bottom slope i,relative water depth d/L_0 and the asymmetry of wave profile than that of regularwaves.The breaker index of regular waves from Goda may be used in the case of irregular waves, whilethe coefficient A should be 0.15.The ratio of irregular wavelength to the length calculated by linear wavetheory is 0.74.Analysis is also made on the waveheight damping coefficient of regular waves after break-ing and on the breaking probability of large irregular waves. 相似文献
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Liu Liping Engineer The Investigation Design Institute of The Second Navigation Engineering Bureau Ministry of Communications P. R. of China Wuhan 《中国海洋工程》1991,(4)
Through numerical modeling, a kind of simplified calculating method for standing wave pressure on vertical face breakwater have been put forward. Not only the formulas proposed in this paper are simple in form and very easy in use, but also they possess continuity on the full range of standing wave. And more, the precision requiremennts of calculation can be satisfied to a certain extent in engineering practice. 相似文献
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通过分析实验室风浪观测结果研究非线性效应对波面极大值和极小值分布的影响。波面极大值和极小值累积概率的差异表明 ,与线性理论相比 ,波面极小值在平均波面以下的位置偏高。对实验结果的进一步分析表明 ,非线性效应使波面极大值在平均波面以上总概率高于线性理论结果 ,而概率密度峰值处波面极大值高度略低于线性理论结果。波面极小值在平均波面以上各位置出现的概率均高于线性理论结果 ,在平均波面以下的较低位置 ,波面极小值出现概率明显低于线性理论结果。 相似文献
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采用新的无量纲变量组合推导出波浪破碎形成的气泡总数与气体体积卷入率、湍流能谱密度以及表面张力之间的关系;利用观测结果提出两点假设,并据此将泡径谱N(a)推广为随泡径和深度的分布函数N(a,z)。 相似文献
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为了提高粒子法即移动粒子半隐式法(Moving Particle Semi-implicit method, MPS法)中自由表面粒子的识别精度,降低由粒子误判引起的非物理压力振荡,对MPS法的自由表面识别方法进行了改进。在原始自由表面判别标准的基础上增加辅助判别条件,提出2种新的自由表面判别法即压力判别法和填充率判别法。利用对静水问题和溃坝流问题的模拟计算,对比分析选用不同自由表面判别法得到的数值计算结果,揭示粒子识别精度对压力计算的重要影响。研究结果表明:新提出的压力判别法和填充率判别法可以有效地提高自由表面粒子的识别精度,减轻压力计算中的非物理压力振荡现象,从而提高压力计算的稳定性以及整体数值计算的模拟精度。 相似文献
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上层海洋中浪致混合研究评述——研究进展及存在问题 总被引:1,自引:0,他引:1
本文较系统地分析和总结了海浪在上层海洋中的混合作用研究的国内外现状,分别探讨了海浪破碎、波生运动以及波-湍相互作用导致的混合作用,指出了现有研究存在的问题。对今后研究做一展望,并指出实验室热分层水槽中的系统实验研究的必要性。 相似文献
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针对固定粒子数PF-TBD算法计算量大、复杂环境下地波雷达海上船只目标检测与跟踪性能不佳的问题,本文将粒子滤波方法应用于地波雷达船只目标检测与跟踪中,提出了基于自适应粒子滤波的地波雷达目标检测与跟踪联合处理方法。该方法结合地波雷达回波谱中目标展宽特性,充分利用了地波雷达回波谱中面目标的粒子权重信息来设置粒子自适应采样策略,提高了目标检测和跟踪联合处理的效果。通过地波雷达实测数据的目标跟踪结果及与同步AIS信息的比对分析,结果表明:提出的检测跟踪联合处理方法在对低信噪比、快速机动等复杂环境下的多目标跟踪时,可提高目标整体跟踪性能。 相似文献
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The wave diffraction and radiation problem is studied numerically by using a higher-order boundary element method. The convergence of the higher-order boundary element method is tested systematically for bodies of different shapes. For the second-order force, particular attention is paid to the contribution of the second-order potential, following the line of Molin's approach. For numerical evaluation, the free surface is divided into three subregions; inner, intermediate and outer ones. In the inner region, the integral is evaluated numerically by using higher-order boundary elements. In the intermediate region, semi-analytic form is constructed with the help of eigen functions. In the outer domain, the analytic solution is available. This subdivision scheme reduces the numerical burden remarkably. 相似文献