共查询到19条相似文献，搜索用时 171 毫秒
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利用青岛海洋大学海洋实验室现代化的大型水槽,设计进行了多种海浪强度下,由深水传入近岸不同坡度水底上的变浅随机海浪的模型实验,依据实验资料统计分析结果表明,对近岸变浅随机海浪而言,其波高分布不再符合Ｒａｙｌｅｉｇｈ分布,与ГЛУФОВСКИЙ的经验分布也有差异,它不仅与参量Ｈ＝Ｈ／ｄ有关,且与表征深水海浪的波形特征量Ｈ０／Ｔ０有关,并获得其经验关系,为实验应用变浅随机海浪的波高统计分布提供了可能。 相似文献
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利用大型水槽设计了在由深水到近岸不同坡度处海浪在变浅作用下诱导产生的长周期重力波的实验。正态随机海浪在深水生成并沿斜坡向浅水传播,记录了不同水深处波面高度随时间的变化过程并进行统计分析和谱分析。实验数据分析结果表明,长周期重力波的能量随着水深的变浅而增高,其谱锋频率位于0.2~0.3fp附近,这里fp是深水正态海浪过程的谱峰频率。长周期重力波的能量与入射波的能量比与波面高度分布的偏度密切相关。进一步分析了两种波动的能量谱峰值比和波面高度分布偏度的相关关系,获得了经验关系,为预测近岸浅水长周期重力波提供了科学依据。 相似文献
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非线性随机海浪模型的一种新形式 总被引：5，自引：1，他引：5
以反映随机海浪非线性的波面高度分布高阶矩为参量，提出一种新形式的非线性随机海浪模型，在三阶近似下具体导出其波面高度的表达工和推导出二阶谱。本文模式为Ｌｏｎｇｕｅｔ－Ｈｇｇｉｎｓ模式的另一种新的数学表示。 相似文献
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变浅作用下浅水海浪谱的计算 总被引：1，自引：0，他引：1
深水海浪向近岸传播过程中,由于变浅作用,其波面高度分布,波谱都发生了变化。本文基于非线性系统的输出和输入间亦存在转换关系,通过波面高度分布函数建立了深水正态海浪过程作为输入和浅水偏态海浪过程作为输出之间的非线性转换关系,导出了深、浅水谱间的理论关系。在假定能通量不变的条件下,提出了一种由已知深水谱和波面偏度计算二维海浪变浅作用下的浅水谱的方法,并对其进行了讨论和检验。 相似文献
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基于非线性Beta波面分布，采用变换ξ=lnH／γ，导出了一种仅用随机波面偏度λ3和尖度λ4两个参数表示的非线性有效波高概率分布——对数-Beta分布，发展了线性海浪有效波高的双参数对数-正态分布。对比结果表明，对数-Beta分布理论曲线与其对应的实测资料符合良好。推导出的对数-Beta分布的优点是，基本参数较少且便于确定，并可由随机波面高度资料直接推导出对应的有效波高概率密度函数。 相似文献
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基于非线性Beta波面分布,采用经验变换,导出1种仅用随机波面偏度λ3和尖度λ4 2个参数表示的非线性海浪波高概率统计分布--波高类Beta分布.此分布发展了线性窄谱假定下的Rayleigh分布.就所用实验室资料验证而言,本文推导的波高类Beta分布要优于几种工程上常用的波高分布. 相似文献
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海浪非线性性的实验研究 Ⅰ.波面高度分布的非正态性 总被引：5，自引：2，他引：5
本文介绍海浪非线性性实验研究的第一部分.利用实验室测得的在各种背景下具有不同非线性强度的风浪波面记录,通过波面统计分析,并与非线性波面理论分布比较,揭示了海浪非线性性的外观特征及其随风速、风区等的变化规律. 相似文献
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基于Longuet－Higgins提出的非线性随机海浪模型，在二阶近似下通过直接计算联合分布的各阶矩，导出了非线性海浪波面高度和波面垂直速度的联合分布。该分布为非正态，其形式为截断的级数，而非由累积矩母函数方法可能得到的渐近无穷级数。由于非线性的影响，波面高度与波面垂直速度不再相互独立。 相似文献
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In this paper, without recourse to the nonlinear dynamical equations of the waves, the nonlinear random waves are retrieved from the non-Gaussian characteristic of the sea surface elevation distribution. The question of coincidence of the nonlinear wave profile, spectrum and its distributions of maximum (or minimum) values of the sea surface elevation with results derived from some existing nonlinear theories is expounded under the narrow-band spectrum condition. Taking the shoaling sea wave as an example, the nonlinear random wave process and its spectrum in shallow water are retrieved from both the non-Gaussian characteristics of the sea surface elevation distribution in shallow water and the normal sea waves in deep water and compared with the values actually measured. Results show that they can coincide with the actually measured values quite well, thus, this can confirm that the method proposed in this paper is feasible. 相似文献
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A nonlinear model for nonbreaking shoaling random waves 总被引：1，自引：0，他引：1
ＡｎｏｎｌｉｎｅａｒｍｏｄｅｌｆｏｒｎｏｎｂｒｅａｋｉｎｇｓｈｏａｌｉｎｇｒａｎｄｏｍｗａｖｅｓＬｉｕＸｉｎ＇ａｎ,ＨｕａｎｇＰｅｉｊｉ,ＣｈｅｎＸｕｅｙｉｎｇ,ＨｕＺｅｊｉａｎ（ＲｅｃｅｉｖｅｄＯｃｔｏｂｅｒ１５,１９９６,ａｃｃｅｐｔｅｄＡｕｇｕ... 相似文献
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数值波浪水槽技术是一种新兴的水波动力学数值模拟技术, 它能够实现水波现象的精确模拟。作为数值波浪水槽的一个重要功能, 消波技术被用于消除传入波浪在水槽末端的反射效应, 以防止反射波对有效实验区域的污染, 从而保证特定要求的水波实验的精确性。目前被广泛采用的消波技术可分为阻尼消波区和主动消波器两类。 相似文献
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为了研究真实海洋表面马蹄波特性以及对建筑物的作用,通过物理模型实验研究了马蹄波的波形特征参数以及马蹄波对圆柱体的作用。实验中通过对浪高仪采集的波面升高时间历程曲线进行分析得出了不同水深情况下马蹄波的垂向几何特征,并通过快速傅里叶变换得出了马蹄波波幅谱的特征,研究了马蹄波各组成波波幅沿空间的变化从而得出了圆柱存在对马蹄波演化的影响,同时给出马蹄波绕射形成的波面分布和不同频率谐波在圆柱周围的分布,讨论了马蹄波不同于Stokes波对圆柱作用的特征。结果表明,马蹄波波形受水深影响较大,水深越浅,马蹄波的波面形状越接近椭圆余弦波。圆柱体的存在干扰了马蹄波不稳定的增长,使其在接近圆柱时呈下降趋势,导致不稳定幅值最大值的位置提前并且出现在偏离圆柱迎浪点的侧表面,从而使圆柱受到侧向力的作用。 相似文献
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《Coastal Engineering》2004,50(4):169-179
Based on the second-order random wave solutions of water wave equations in finite water depth, a joint statistical distribution of two-point sea surface elevations is derived by using the characteristic function expansion method. It is found that the joint distribution depends on five parameters. These five parameters can all be determined by the water depth, the relative position of two points and the wave-number spectrum of ocean waves. As an illustrative example, for fully developed wind-generated sea, the parameters that appeared in the joint distribution are calculated for various wind speeds, water depths and relative positions of two points by using the Donelan and Pierson spectrum and the nonlinear effects of sea waves on the joint distribution are studied. 相似文献
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This paper provides an approach by which the scour depth below pipelines in shoaling conditions beneath non-breaking and breaking random waves can be derived. Here the scour depth formula in shoaling conditions for regular non-breaking and breaking waves with normal incidence to the pipeline presented by Cevik and Yüksel [Cevik, E. and Yüksel, Y., (1999). Scour under submarine pipelines in waves in shoaling conditions. ASCE J. Waterw., Port, Coast. Ocean Eng., 125 (1), 9–19.] combined with the wave height distribution including shoaling and breaking waves presented by Mendez et al. [Mendez, F.J., Losada, I.J. and Medina, R., (2004). Transformation model of wave height distribution on planar beaches. Coast. Eng. 50 (3), 97–115.] are used. Moreover, the approach is based on describing the wave motion as a stationary Gaussian narrow-band random process. An example of calculation is also presented. 相似文献
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Lou Jing P.V. Ridd C.L. Mayocchi M.L. Heron 《Estuarine, Coastal and Shelf Science》1996,42(6):787-802
Waves propagating from deep water into shallow coastal areas produce oscillatory currents near the sea bottom. The magnitude of these currents depend upon the period and amplitude of the incoming waves, and the dissipation mechanism such as wave breaking and bottom friction. Field experiments in a gently shoaling bay, i.e. Cleveland Bay, Northern Australia, showed that there is a broad band of water at around 6 m depth, where the benthic surge velocities are maximum. Both further inshore and offshore, the bottom velocities were less than at 6 m depth, contrary to the normal expectation that the velocities should increase as the water becomes shallower. A new and computationally efficient wave model was developed and was able to reproduce experimental results for waves above 50 cm wave height, but not for small waves (wave height about 30 cm). One implication of this higher band of benthic surge velocities may be to produce high water turbidities in this region. Turbidity data from Cleveland Bay is consistent with this hypothesis. 相似文献
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Kern E. Kenyon 《Journal of Oceanography》2006,62(6):923-927
Surface gravity waves are commonly observed to slow down and to stop at a beach without any noticeable reflection taking place.
We assume that as a consequence the waves are continuously giving up their linear and angular momenta, which they carry with
them, along with energy, as they propagate into gradually decreasing mean depths of water. It takes a force to cause a time
rate of decrease in the linear momentum and a torque to produce a time rate of decrease in the angular momentum. Both a force
and a torque operate on the shoaling waves, due to the presence of the sloping bottom, to cause the diminution of their linear
and angular momenta. By Newton’s third law, action equals reaction, an equal but opposite force and torque are exerted on
the bottom. No other mechanisms for transferring linear and angular momenta are included in the model. Since the force on
the waves acts over a horizontal distance during shoaling, work is done on the waves and energy flux is not conserved. Bottom
friction, wave interaction with a mean flow, scattering from small-scale bottom irregularities and set-up are neglected. Mass
flux is conserved, which leads to a shoreward monotonic decrease in amplitude consistent with available swell data. The formula
for the time-independent force on the bottom agrees qualitatively with observations in seven different ways: four for swell
attenuation and three for sediment transport on beaches. Ardhuin (2006) argues against a mean force on the bottom that is
not hydrostatic, mainly by using conservation of energy flux. He also applies the action balance equation to shoaling waves.
Action is a difficult concept to grasp for motion in a continuum; it cannot be easily visualized, and it is not really necessary
for solving the shoaling wave problem. We prefer angular momentum because it is clearly related to the observed orbital motion
of the fluid particles in progressive surface waves. The physical significance of wave action for surface waves has been described
recently by showing that in deep water action is equivalent to the magnitude of the wave’s orbital angular momentum (Kenyon
and Sheres, 1996). Finally, Ardhuin requires that there be a significant exchange of linear momentum between shoaling waves
and an unspecified mean flow, although the magnitude and direction of the exchange are not predicted. No mention is made of
what happens to the orbital angular momentum during shoaling. Mass flux conservation is not stated. 相似文献