琼州海峡的波浪特征

本文依据多年实测波浪资料揭示了琼州海峡的波浪特征，结果表明，本海域以风浪为主，其出现频率占７６．７％以上。波浪随季节变化显显，觉浪向和强浪向频为一致它们是ＮＥ－ＥＮＥ。一般来说，本海区的最大波浪是由台风产生的；海峡两端海区的波浪比中闻海区的大。     

香港附近海域强冷空气影响下波浪特征及谱拟合

本文以香港附近海域二次冷空气影响下的波浪实测资料为依据,讨论了波浪特征与谱的拟合。这二次实测,一次为波浪成长阶段,而另一次为波浪衰减阶段。而文中的(1),(2)式代表的涌浪谱公式和文献(7)中提出的风浪谱公式不仅适合于香港附近海域强冷空气影响下的海浪谱,而且可以表征南海其它海区不同季节的海浪谱,所以具有很强的适用性。     

台风作用下琼州海峡海域波浪特征分析

通过在拟建琼州海峡跨海大桥西线方案主通航孔位置布置波浪测点,采集到2012年13号台风"启德"和23号台风"山神"期间波浪数据,结合两场台风期间波浪频谱和方向谱的变化,分析了该区域在台风期间的波浪特征,并进一步对风浪和涌浪进行了判别。研究结果表明:1)台风"启德"期间,海域波浪谱峰周期在3.3⁸.0 s之间,最大谱峰值为7.92 m2/s,波浪方向为W8.0 s之间,最大谱峰值为7.92 m2/s,波浪方向为W^N向,且频谱和方向谱的变化过程反映了风浪到涌浪的转变;2)台风"山神"期间,海域波浪谱峰周期在5.0N向,且频谱和方向谱的变化过程反映了风浪到涌浪的转变;2)台风"山神"期间,海域波浪谱峰周期在5.0⁶.5 s之间,最大谱峰值为2.70 m2/s,波浪方向为E6.5 s之间,最大谱峰值为2.70 m2/s,波浪方向为E^ESE向,波浪以风浪为主;3)琼州海峡海域大周期波浪主要受到台风引起的涌浪影响,涌浪周期的范围大约在6.5ESE向,波浪以风浪为主;3)琼州海峡海域大周期波浪主要受到台风引起的涌浪影响,涌浪周期的范围大约在6.5¹0.0 s之间。     

波浪在浅水传播中的弱非线性效应

在波浪从深水向浅水传播过程中,考虑弱非线性效应具有重要的实用价值,因此得到广泛的讨论和研究。本文根据文献「６」导出的考虑能耗的定常缓坡方程,结合文献「５」给出的显式非线弥散关系,得出了含弱非线性效应的缓坡方程,用该方程对浅水中波浪的传播 计算,将计算结果和试验数据进行了比较,结果表明,含弱非线性效应的缓坡方程可以用于讨论浅水中波浪传播的弱非线性效应,所得计算计算结果与试验结果更为吻合。     

北部湾沿岸海区设计波浪的确定

本文基于北部湾沿岸海区多年的实测资料，于不同海区主浪向和次主浪向分别取年极值波高为样本资料．采用Ｐ－Ⅲ型和短期测波资料频率分析方法，分别估算了各海区不同重现期的设计波高，并依据式（１）计算出相应的平均周期。尽管样本资料和估算方法不变，但每次估算的结果互不相同，其差异甚至很大．利用Ｋｏｌｍｏｇｏｒｏｆｆ等适合度方法检验所得的结果，能够准确地判断出沿岸各海区不同重现期的最佳设计波浪。     

“烟花”台风影响下长江口水域波浪分布特征研究

台风往往会带来强风、大浪、风暴潮。强潮大浪给长江口深水航道整治工程的维护带来挑战。构建了覆盖中国海的台风浪—风暴潮耦合数学模型,模拟了台风“烟花”作用下长江口北槽水域波浪的发展过程,分析了长江口北槽水域波浪分布特点和台风强度。研究表明：叠加风场和潮汐模式共同驱动的台风浪―风暴潮耦合模型,可以准确模拟台风期间长江口水域波浪的生成和发展过程;“烟花”台风期间,外海大浪以东方向浪为主,长江口北槽南挡沙堤沿线有效波高最大值介于1.61~5.22 m之间,自东向西逐渐衰减;台风过程中,长江口北槽水域有效波高在台风二次登录时刻达到最大,口门处有5. 0 m以上大浪;依据台风过程中长江口风速及外海波高、周期与参考规范值对比分析得出,“烟花”台风过程波浪强度约为50年一遇。     

深海平台立柱周围波浪非线性爬升研究进展

随着深海油气田的不断开发,各种适应深海环境的浮式平台陆续涌现。多数深海平台通过立柱支撑上层甲板,波浪沿柱体表面的爬升效应极为明显,大大增加了强非线性砰击和越浪的危险,甚至将导致平台局部结构以及相关设备的破坏。因此,波浪爬升效应在平台设计及结构安全性方面具有重要的意义,并成为平台水动力研究的热点问题之一,是平台气隙预报的一个重要方面。介绍波浪爬升效应在平台设计阶段的重要性,分析波浪爬升的成因和影响因素,就目前国际上相关研究情况及进展进行了详细的阐述,并提出了这一课题未来研究方向的有关建议。     

南海灾害性波浪基本特征研究

本文基于1991-2016年全球卫星高度计融合数据对南海灾害性波浪基本特征进行了分析,根据灾害性波浪诱发天气类型不同,将其分为"台风浪"和"非台风浪"。依此主线,对两类波浪在南海不同海域的特征进行了研究,并提出了用于定量研究两类波浪强度关系的台风浪权重系数（W）,得到了两类波浪在南海相对强弱关系的分布规律,量化研究了南海灾害性波浪的特征。本文以卫星高度计波高数据为样本进行了极值分析,得到了南海重现期波浪要素整体分布规律,研究发现W值大小与广义极值曲线类型显著相关。     

塘沽近海海域海浪的基本特征

本文对在海洋钻井平台上连续观测6a的波浪资料进行了统计、分析，结果表明，本区大浪主要发生在秋季，多年按月统计极值波高11月最大，为5．3m（东北向），7月最小，为2．8m；波浪总特征表现为秋季强，春季次之，夏季最弱的特征。表中所示波浪特征值，在塘沽海城海洋工程建设中具有重要的价值．     

南海北部波浪特征分析

利用南海北部近海区域(20°36.298′N,110°45.433′E)于2012年至2013年的波浪实测资料,统计分析了其波浪特征,为海洋工程建设和波浪能利用提供基本波浪参数。统计结果表明,南海北部年平均有效波高为1.2m,周年平均十分之一部分大波波高为1.5m,年平均周期4.0s,周年最大平均有效波高为4.97m,周年最大平均十分之一部分大波波高为7.34m,常浪向为E向,次常浪向为ENE向。强浪向为E向,次强浪向为ESE向。     

琼州海峡的一个三维泥沙扩散模式

通过建立一个三维陆架海数值模式来预报近海潮流和泥沙浓度的对流扩散,并应用于琼州海峡跨海工程的前期数值预测。预测结果表明,海区潮流的涨落、岸线形状、海底地形及源强位置与泥沙在近海的输运扩散关系密切,模拟情形基本合理,表明该模式适合应用于河口、近岸等涉海海洋工程海域的流场及泥沙扩散的三维数值预测,为相关的水动力环境要素和水质影响评价提供一定的参考价值。     

Wave modelling - The state of the art

This paper is the product of the wave modelling community and it tries to make a picture of the present situation in this branch of science, exploring the previous and the most recent results and looking ahead towards the solution of the problems we presently face. Both theory and applications are considered.The many faces of the subject imply separate discussions. This is reflected into the single sections, seven of them, each dealing with a specific topic, the whole providing a broad and solid overview of the present state of the art. After an introduction framing the problem and the approach we followed, we deal in sequence with the following subjects: (Section) 2, generation by wind; 3, nonlinear interactions in deep water; 4, white-capping dissipation; 5, nonlinear interactions in shallow water; 6, dissipation at the sea bottom; 7, wave propagation; 8, numerics. The two final sections, 9 and 10, summarize the present situation from a general point of view and try to look at the future developments.     

琼州海峡白沙门海滩冲淤的遥感分析

琼州海峡白沙门海滩是海口市重要旅游资源,历史研究表明自20世纪60年代以来其一直处于侵蚀退化状态。本文选取1994—2015年的19景Landsat遥感影像提取白沙门海滩水边线并计算海滩坡度,分析海滩冲淤,结果表明:1994—2008年海滩处于冲刷状态,高潮位的水边线平均向岸回退了104.71 m, 低潮位的水边线平均向岸回退了95.49 m,但是2000年附近时段的人工补沙弥补了海滩侵蚀退化;2008—2015年海滩转为淤积状态,高潮位的水边线平均向海前进了34.17 m,低潮位的水边线平均向海前进了25.52 m,海滩淤积可能是海滩东侧的新埠岛围填海工程造成的。     

Wave attenuation and dispersion due to floating ice covers

Experiments investigating the attenuation and dispersion of surface waves in a variety of ice covers are performed using a refrigerated wave flume. The ice conditions tested in the experiments cover naturally occurring combinations of continuous, fragmented, pancake and grease ice. Attenuation rates are shown to be a function of ice thickness, wave frequency, and the general rigidity of the ice cover. Dispersion changes were minor except for large wavelength increases when continuous covers were tested. Results are verified and compared with existing literature to show the extended range of investigation in terms of incident wave frequency and ice conditions.     

Wave prediction using wave rider position measurements and NARX network in wave energy conversion

Several control methods of wave energy converters (WECs) need prediction in the future of wave surface elevation. Prediction of wave surface elevation can be performed using measurements of surface elevation at a location ahead of the controlled WEC in the upcoming wave. Artificial neural network (ANN) is a robust data-learning tool, and is proposed in this study to predict the surface elevation at the WEC location using measurements of wave elevation at ahead located sensor (a wave rider buoy). The nonlinear autoregressive with exogenous input network (NARX NN) is utilized in this study as the prediction method. Simulations show promising results for predicting the wave surface elevation. Challenges of using real measurements data are also discussed in this paper.     

Wave field mapping with particle image velocimetry

A number of different methods for the 3D measurement of the water surface in wave fields have been proposed in the literature, based mostly on refraction, photogrammetry and/or reflected light intensity. Although these methods can map the distorted water surface, they appear to be difficult in practical applications in hydraulic engineering laboratories. A novel wave mapping technique using particle image velocimetry to measure surface flow velocities, and linear wave theory to determine wave heights from the measured velocities, has been developed and validated for regular waves. The method allows for the mapping even of complex wave fields with simple means and appears robust enough for application in the laboratory.     

Wave reflection in 3D conditions

Based on recent experiments carried out in wave basin on breakwaters with armour layer of rocks and cubes, this paper examines the dependence of the reflection coefficient on wave directional spreading and obliquity. Results suggest that long-crested and short-crested waves give similar reflection. The reflection coefficient is markedly dependent on the wave angle of incidence. The performance of formulae available in the literature is checked against the new dataset and a significant improvement is proposed by including the wave obliquity factor that appears in the traditional expression for the overtopping discharge.     

Wave actions on the side caissons of the Venice gates

The present study originates from a construction problem found in the planned deployment of the side caissons of the Venice gates barrier. Each of these caissons is made to float, then sunk into a lateral trench and jointed to the soil at its bottom. As a result, a C-shaped channel forms between the vertical caisson surfaces and the surrounding trench. Incoming storm waves propagating from the sea can then induce forced oscillations in this C-channel. An analytical model based on the method of matched asymptotics is developed in order to obtain the free surface oscillations in the channel, caused by a grazing incident wave. The resonant response of the basin and the amplification factors are then determined. From the free surface elevation, the pressure field and hence the total forces are also found. The analysis moves on to irregular wave motion. The analytical solution enables us to compute the dynamic actions, showing that their magnitude can be significant, due to the excitation of different resonant modes.