共查询到19条相似文献，搜索用时 171 毫秒
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采用目前国际上最新的随机波分析方法,由协方差矩阵的循环嵌套技术,对美国国家浮标44008站2002年6月一典型的双峰海浪谱资料进行谱分析.以实测平均谱为靶谱,对随机波面进行模拟.得到模拟波面估计谱与实测谱极为相近,谱峰及谱峰频率都基本一致.说明利用模拟波面研究海浪具有代表性,它可以反映实测海浪的特征.利用实测海浪谱密度,统计波特征量的周期概率分布,得到理论周期概率密度与估计周期概率密度分布相符较好,且与模拟波面的波周期分布也较好的一致.利用Longuet-Higgins(1983)模型计算了波高-周期联合概率密度分布.得到变换高斯过程计算的波高与周期联合分布与实测情况基本相同,更好地描述了波高-周期联合概率密度分布. 相似文献
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海浪谱高阶谱矩的计算 总被引：1，自引：0，他引：1
分析了海浪谱高阶谱矩不存在的原因。在Ｇｌａｚｍａｎ研究结果的基础上计算了目前工程上常用的ＰＭ谱和ＪＯＮＳＷＡＰ谱的０阶到８阶的谱矩值,以方便实际工程的应用。 相似文献
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研究了基于GPS高频数据进行海浪测量的方法。利用TRACK解算得海上载体高精度的垂向位移,经浪潮分离提取海浪信号,分别采用相关函数法和周期图法估计海浪信号的功率谱,并计算海浪要素。利用实测数据进行试验,结果表明,周期图法推算的平均波高和平均周期精度较高,与测波仪结果差异分别小于2cm和0.25s,基于GPS高频数据的海浪测量方法可有效反演海浪要素。 相似文献
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外观海浪谱的比较和验证 总被引：4，自引：0，他引：4
不同于通常意义下的海浪谱(以下简称为“内频谱”),外观海浪谱描述的是海浪能量随外观频率的分布,它可以依据表征海浪外观统计特征的波高与调期联合分布从理论上确定.本文在Huang、孙孚等已有工作的基础上,对外观海浪谱进行了较为深入的研究.首先,纠正了Huang等论文中的某些错误,并将Huang、孙孚等据不同的联合分布导出的外观海浪谱进行比较;然后,分别计算这两种外观海浪谱的前三阶矩,并与内频谱的矩进行比较;最后,用实验和现场资料对从理论上导出的外观海浪谱进行验证.结果发现,当谱宽度v≤0.3时,外观海浪谱矩与内频谱矩差异很小,理论谱形与实测结果也非常接近.因而,在实际问题的应用中,若谱宽度不大,则就可以用本文讨论的外观海浪谱去替代目前从理论上尚不能得到的通常意义下的海浪谱. 相似文献
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微尺度滑动平均方法计算海浪谱奇阶矩的公式 总被引：2，自引：0，他引：2
Glazman提出了一种计算海浪谱高阶谱矩的微尺度平均方法,但是,他利用随机过程理论导出的计算偶阶矩的公式和参照偶阶矩结论定义的奇阶矩计算公式之间存在着内在的不一致性.本文在Glazman工作的基础上根据随机过程理论推导了“微尺度平均方法”计算奇阶谱矩的公式,纠正了他的错误.上述结论随即应用于讨论破碎对波面水质点水平速度分布的影响.通过破碎的加速度判据考虑了破碎对速度分布的限制,给出了未破碎波面上水质点水平速度的的统计分布的初步结果.该分布取决于谱宽度参数及白浪覆盖率的大小,当白浪覆盖率较大时明显偏离正态分布. 相似文献
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利用TOPEX高度计和NDBC浮标同步观测数据,对7种高度计海浪周期反演模型进行了系统的比较分析,从反演模式的精度、反演周期整体分布、周期-波高的联合分布等方面对反演模型做出了评价,并根据墨西哥湾和夏威夷海域反演结果对模型的区域适应性进行了验证,结合Hasselmann风浪充分成长关系分析了不同海浪成分下模型的反演效果.分析发现,Mackay等于2008年提出的算法(简称M08)相对于其他算法精度最高,且在不同海域和不同海浪成分下精度没有明显差异.利用M08算法反演了北太平洋海域的海浪平均周期分布,讨论其空间分布特征和季节变化特征如下:北太平洋海域的平均周期在墨西哥湾、西里伯斯海等沿岸地区较小,在西风带海域为较大,并存在明显的地形、纬度差异和季节性变化特征. 相似文献
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本文给出应用实测波浪数据确定JONSWAP谱参数的方法，若Hs,Tz,Tc分别为实的有效波高，平均上跨零线周期，平均峰－峰周期并令y=Tz/Tc，本文导出求解谱参数γ值的方程f（γ，y）＝0。根据这个方程的解并应用最小二乘法，γ作为y的函数的表达式可写为（对于2.54≤γ≤15.34及1.6≤y≤1.79）。 相似文献
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The relationship between significant wave height and period, the variability of significant wave period, the spectral peak enhancement factor, and the directional spreading parameter of large deepwater waves around the Korean Peninsula have been investigated using various sources of wave measurement and hindcasting data. For very large waves comparable to design waves, it is recommended to use the average value of the empirical formulas proposed by Shore Protection Manual in 1977 and by Goda in 2003 for the relationship between significant wave height and period. The standard deviation of significant wave periods non-dimensionalized with respect to the mean value for a certain significant wave height varies between 0.04 and 0.21 with a typical value of 0.1 depending upon different regions and different ranges of significant wave heights. The probability density function of the peak enhancement factor is expressed as a lognormal distribution, with its mean value of 2.14, which is somewhat smaller than the value in the North Sea. For relatively large waves, the probability density function of the directional spreading parameter at peak frequency is also expressed as a lognormal distribution. 相似文献
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The spectral characteristics of shallow water waves with significant wave height more than 2 m based on the data collected along the Indian coast is examined. It was found that the value of Joint North Sea Wave Project (JONSWAP) parameters (α and γ) increases with significant wave height and mean wave period and decreases with spectral peak period. The estimated average value (0.0027 and 1.63) of the JONSWAP parameters, α and γ were less than the generally recommended values of 0.0081 and 3.3, respectively. By carrying out a multi-regression analysis, an empirical equation is arrived relating the JONSWAP parameters with significant wave height, peak wave period and mean wave period. It was found that the Scott spectra underestimate the maximum spectral energy of high waves. The study shows that the measured wave spectra can be represented by JONSWAP spectra with the JONSWAP parameters estimated based on the equation proposed in this paper. 相似文献
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Eugen Rusu 《Ocean Engineering》2011,38(16):1763-1781
An evaluation of two state of the art phase averaged wave models for the transformation scale, SWAN and STWAVE, is carried out in the present work. The target area is the Obidos Bay located in the central part of the Portuguese continental nearshore. The wave input for the two models is provided by an offshore buoy. In order to compare the nearshore outputs of the wave models against in-situ measurements, a directional buoy and an ADCP, operating in intermediate water depth, are used. The wave parameters considered for comparisons are significant wave height, peak period and wave direction. Sensitivity analyses studies and evaluations in the spectral and geographical spaces concerning the results of the two models are also carried out in both intermediate and shallow water. The present study provides some information on the performances of the two wave models in different forcing conditions as well as on their sensitivity in relationship with various input parameters and some physical processes. STWAVE appears to be faster and more robust than SWAN, which on the other hand has more options and flexibility. In statistical terms the results are comparable. 相似文献
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The uncertainty of some commonly used spectral wave parameters resulting from the spectral estimation procedure is assessed. It is observed that the methods of spectral estimation produce a significant uncertainty for all parameters examined, but this is of considerable importance only for the peak period, which is one of the most important parameters to model the wave climate. 相似文献
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基于浅水斜坡地形的物理模型试验数据,考察SWAN模型对实验室小尺度浅水波浪的模拟效果,进而检验其浅水项的模拟精度。模拟中采用直接输入初始测点的实测海浪谱进行造波,重点考察浅水中三波相互作用和变浅破碎两个源项,对不同工况下,SWAN模式在水深条件变化下的有效波高、谱平均周期、海浪谱演化的模拟能力进行研究。研究表明:模拟的有效波高较符合实测波浪的增长和衰减,但谱平均周期计算值明显偏小;海浪谱的能量转移机制同实测有较大区别,频谱模拟结果出现高频高估、低频低估现象。对两个源项进行对比分析得出三波相互作用对海浪谱的能量转换影响远大于变浅破碎耗散。想要提高近岸区谱平均周期和海浪谱的模拟精度则SWAN模型中三波非线性项的计算精确度仍需更多研究和改进。 相似文献
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Wave and wind characteristics based on the cyclones, in the vicinity of the Nagapattinam coastline (east coast of India) were estimated. In all, 11 cyclones have crossed near the study region during 1960–1996. For the four severe cyclones, the isobaric charts were collected at three hourly intervals from the India Meteorological Department. The storm variables such as central pressure, radius of maximum wind, speed of forward motion and direction of storm movement were extracted and the method based on standard Hydromet pressure profile, were used for the hindcast of storm wind fields. For all the cyclones the maximum significant wave height within the storm and its associated spectral peak period was estimated using the Young’s model considering the moving wind field and the results are compared with the hurricane wave prediction techniques provided in the shore protection manual published by the US Army Corps of Engineers in 1984. The study shows that the estimated wind speed and the data reported by ships were comparable. Empirical expressions relating wind speed, wave height and wave period to storm parameters were derived. The design wave height for different return periods was obtained by fitting a two-parameter Weibull distribution to the estimated significant wave heights. The design wave height was 9.39 m for 1 in 100 year return period for a direct hit of cyclone. 相似文献
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OSMAR-S系列便携式高频地波雷达系统采用单极子/交叉环紧凑型天线阵,通过单站雷达即可实现有效探测距离约10km内海浪和海面风的单点观测。为了更好地了解OSMAR-S100雷达系统海浪和海面风的综合探测性能,于2013年1月29日至3月7日在台湾海峡西南部海域进行了雷达与浮标观测的对比试验,得到了有效波高、有效波周期、平均风速和平均风向数据。对比结果表明,OSMAR-S100便携式高频地波雷达可有效观测距雷达10km以内有效波高0.5m以上的海浪平均状况和平均风速5m/s以上的海面风,雷达反演有效波高和有效波周期的均方根误差分别为0.60m和1.60s,反演平均风速和平均风向的均方根误差为1.83m/s和16.7°。在未经区域化标定的情况下,此结果说明了该型雷达产品已初步具备了海浪和海面风的业务化观测水平。 相似文献
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In this paper, we present and evaluate three long-term wave models for application in simulation-based design of ships and marine structures. Designers and researchers often rely on historical weather data as a source for ocean area characteristics based on hindcast datasets or in-situ measurements. The limited access and size of historical datasets reduces repeatability of simulations and analyses, making it difficult to assess the sampling variability of performance and loads on marine vessels and structures. Markov, VAR and VARMA wave models, producing independent long-term time series of significant wave height (Hs) and spectral peak period (Tp), is presented as possible solutions to this problem. The models are tested and compared by addressing how the models affect interpretation of design concepts and the ability to replicate statistical and physical characteristics of the wave process. Our results show that the VAR and VARMA models perform sufficiently in describing design performance, but does not capture the physical process fully. The Markov model is found to perform worst of the tested models in the applied tests, especially for measures covering several consecutive sea states. 相似文献
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The paper provides a joint distribution of significant wave height and characteristic surf parameter. The characteristic surf parameter is given by the ratio between the slope of a beach or a structure and the square root of the characteristic wave steepness in deep water defined in terms of the significant wave height and the spectral peak period. The characteristic surf parameter is used to characterize surf zone processes and is relevant for e.g. wave run-up on beaches and coastal structures. The paper presents statistical properties of the wave parameters as well as an example of results corresponding to typical field conditions. 相似文献