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风浪方向分布模式的比较 总被引：2，自引：0，他引：2
本文对目前常用的几种风浪方向分布模式进行了分析对比，进而根据由浪高仪阵列和ＥＮＤＥＣＯ９５６测波浮标在我国各海区测得的风浪方向谱，从波能方向分布、方向累积分布、方向分布的峰值和标准差四个方面，与光易恒、Ｈａｓｓｅｌｍａｎｎ和Ｄｏｎｅｌａｎ等分别由观测得到的经验方向分布以及文圣常等由解析方法得到的风浪方向谱进行了比较，结果表明：Ｄｏｎｅｌａｎ分布与实测结果比较一致，文圣常谱也较接近。此外，笔者在渤海由仪器阵列实测方向谱拟合得到的方向分布（改进的光易模式）与各地实测资料也比较符合。 相似文献
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Okey Nwogu 《Applied Ocean Research》1989,11(4):176-182
A procedure for estimating directional wave spectra from an array of wave probes based on the Maximum Entropy Method (MEM) is developed in the present paper. The MEM approach yields an angular spreading function at each frequency band consistent with the input cross-spectral density matrix. The method is evaluated using numerical simulations of directional sea states. The MEM is also used to analyze data obtained from the three-dimensional wave basin of the Hydraulics Laboratory, National Research Council of Canada. Finally, the MEM is compared with the Maximum Likelihood Method (MLM) and is shown to be a powerful tool for directional wave analysis. 相似文献
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波浪聚焦被认为是产生极限波浪的重要机理之一,近年来受到普遍重视。通过高阶谱方法,引入造波边界建立数值计算模型,模拟聚焦波浪在不同方向分布时的产生和聚焦过程,研究波浪的方向分布对聚焦波浪的波面、波峰最大值、聚焦点的偏移、波面参数及频谱的影响。研究结果表明波浪方向分布越窄,波浪的非线性影响越强、波面越陡,波峰值、聚焦点的偏移和波面特征参数都越大;同时方向分布对波浪聚焦前后的能量具有很大的影响。 相似文献
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measurements by a circular array consisting of 18 wave gauges in a large wave tank, directional spectra of wind-generated waves in deep water are systematically determined by using maximum likelihood method The investigations reveal that the angular spreading of the wave energy is consistent with cos2s(θ/2) proposed by Longuet-Higgins et al.(1963, Ocean Wave Spectra, 111-136), if the bimodal distributions of wave energy are not taken into account. Bimodality occurring on higher frequency than peak frequency is too rare to affect our whole resalts. Surprisingly, a much broader directional spreading than that of the field, which is interpreted by the strongly nonlinear energy transfer because of the very young waves in laboratory, is found. The parameter s depends on frequency in the same way as observed by Mitsuyasu et al.(1975, Journal of Physical Oceanography, 5, 750-760) and Hasselmann et al.(1980, Journal of Physical Oceanography, 10, 1264-1280) in the field, and the relationship between the four nondimensional parameters sm, fo, b1 and b2, determining the directional width, and ū10 (corresponding to the inverse of wave age) are given respectively. The observed distributions are found to agree well with the suggestion of Donelan et al.(1985, Philosophical Transaction of Royal Society of London, A315, 509-562) when applied to field waves. 相似文献
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The characteristics of directional spread parameters at intermediate water depth are investigated based on a cosine power ‘2s' directional spreading model. This is based on wave measurements carried out using a Datawell directional waverider buoy in 23 m water depth. An empirical equation for the frequency dependent directional spreading parameter is presented. Directional spreading function estimated based on the Maximum Entropy Method is compared with those obtained using a cosine power ‘2s' parameter model. A set of empirical equations relating the directional spreading parameter corresponding to the peak of wave spectrum to other wave parameters like significant wave height and period are obtained. It shows that the wave directional spreading at peak wave frequency can be related to the non-linearity parameter, which allows estimation of directional spreading without reference to wind information. 相似文献
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New version of SWAN model includes the wave diffraction effect which is the main improvement compared with the previous versions.Experimental data collected in the wave basin of the University of Delaware were used to test its performance.Wave heights were compared in the four cases(with different wave energies and directional spreading spectra).The results agreed well with the measurements,especially for the broad directional spectra cases.The effect of wave diffraction was analyzed by switching on/off the corresponding term.By introducing the diffraction term,the distributions of wave height and wave direction were smoothed,especially obvious for the narrow spectrum cases.Compared with the calculations without diffraction,the model with diffraction effect gave better results. 相似文献
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In this paper, the modified Bayesian method for the analysis of directional wave spectra and reflection coefficients is verified by numerical and physical simulation of waves. The results show that the method can basically separate the incident and reflected directional spectra. In addition, the effect of the type of wave gage arrays, the number of measured wave properties, and the distance between the wave gage array and the reflection line on the resolution of the method are investigated. Some suggestions are proposed for practical application. 相似文献
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Wilson方法和井岛方法均是移动风区上著名的波浪推算方法,被广泛应用于台风波浪的推算和预报上。本文通过分析指出:使用上述方法以海洋工程界所推行的风浪预报公式作台风浪推算时,所得特征波波陡将与台风浪实测波陡分布定性不符,并指出产生这种缺陷的原因。 相似文献
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由量纲分析导出海面粗糙度与波龄及海面涌浪的状况有关,并对与波龄和波陡有关的两种海面粗糙度模型方案进行了敏感性测试,得出利用波龄模型方案计算粗糙度的误差比利用波陡模型方案小。基于国际上6个不同水深、风区和海况条件的海气交换试验资料,将其分为两组,一组是纯风海或以风海为主海况条件,另一组是以涌浪为主海况条件,测试波龄、波陡模型海面粗糙度方案在不同试验条件下的适用性。结果得出:在各种海况条件下,波龄模型粗糙度方案比波陡模型具有更好的普适性。在纯风海或以风海为主海况条件下,PS07,DGHQ03方案计算的粗糙度长度与实测资料计算结果最接近,GW06方案次之,O02方案计算结果明显偏高;涌浪为主海况条件下两种模型方案计算的粗糙度长度均偏低,O02方案计算的粗糙度长度误差相对较小,TY01方案误差最大。 相似文献
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A numerical wave tank is established based on two-phase FVM model and VOF method and verified with the physical experiment in Grue et al. (1994). Focusing waves with different wave steepness passing a vertical cylinder are investigated by Numerical simulations. The phenomenon called ‘secondary load cycle’ which may lead to ringing response, is observed and discussed. The presence of secondary load cycle could be related to Froude Number (Fr). The possible transition region of the present and absent secondary load cycle is Fr = 0.4. Sub and super harmonic wave components appear in the propagation of waves, second-order wave theory could give a good prediction. Morison equation with linear wave theory could predict well the wave forces of vertical cylinder with small steepness without the secondary load cycle, but cannot capture the crests/troughs of the wave forces with the secondary load cycle. Crest improvements are achieved by second-order wave theory. A spectral analysis based on wavelet transform is applied to wave loads. The frequency of the secondary load may be up to 13 times the wave frequency, which may cause the ringing response expanding to a higher frequency range. Strong ringing response occurs in steep wave, it could be extended up to 15 times wave trough-to-trough frequency due to the secondary load cycle. The damping has slightly influence on the peak of resonance response, but it will lead to faster decay of subsequent response, if the damping ratio is large. 相似文献
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为了研究独立高斯型波群在中等水深条件下的非线性演化情况,进行了多种波况的物理试验,重点分析了波浪各要素对波群非线性演化的影响。试验结果表明,波陡在波群演化中占主导作用,其次是波群的谱宽,前者引起的非线性主要体现在高阶谐波的能量变化而后者引起的非线性主要体现在自由波能量的变化。频带下移现象只在大波陡情况下才会发生,随着波陡的增加,频带下移发生的相对更早,随着波群的谱变窄,频带下移相对越明显。波陡的增加会使得波群更早的开始分裂。大波陡的波群在演化中会发生破碎,破碎的类型以崩破为主,并且崩破是间歇发生的,连续崩破发生的距离约为1.0～1.5倍波长。此外,破碎引起的能量损耗主要来源于主频和高频成分波,耗散率约10%～18%,平均每个崩破能耗约为初始能量的2%。 相似文献
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INTRODUCTIONForavarietyofapplications,includingcoastalandoceanengineering,shiproutingandtheinterpretationofremotelysensedata,informationonthedirectionalwavespectrumisdesirable.Knowledegeoftheintegratedorone-dimensionalspectrumisconsiderable,duelargelytofieldmeasurementssuchasJONSWAP.Asimilarsituation,however,doesnotexistinthecaseofdirectionalsprectra.Thisislargelyduetotheaddedcomplexityandthecostofdirectionalmeasure1.InstituteofPhysicalOceanography,OceanUniversityofQingdao,Qingdao266… 相似文献
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Current specification of the ocean wave environment for the design of offshore platforms does not adequately describe the directional nature of a real seaway. The strong wave frequency dependent nature of the directional behavior of observed seas is often over-simplified for design. A general formulation encompassing a wide range of directional sea models is presented. Parameter values used in some of the more popular directional sea models are examined. Approximate expressions for the two frequency dependent parameters in a modified Longuet-Higgins cosine wave spreading model are presented. A general procedure which allows an engineer to estimate parameters for alternate wave spreading models is discussed. To illustrate this procedure an empirically based modified cosine spreading model is used as the basis to estimate frequency dependent parameters for circular normal and wrapped Gaussian wave spreading models. A comparison of the contours of the various directional sea models and the prediction of the root-mean-square velocity distribution is presented. 相似文献
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群发性是风浪破碎的显著特征,最近的研究表明风浪破碎研究应该基于波群而不是单个波。本文探讨破碎波群区别于非破碎波群的显著特征指标。依据一系列风浪破碎实验数据,采用多种判据与实验现场目测的破碎标记信号相结合的原则划分破碎波群与非破碎波群,考查波群特征量、单个波几何特征量、局地破碎判据指标、波包络几何特征量以及波群能量结构特征量等5大类28个指标在破碎波群与非破碎波群上的分布差异。结果表明:波陡、峰前波陡、瞬时波面斜率、运动学判据指标和动力学判据指标等在破碎非破碎波群上的分布几乎没有交叠;后两者尤为理想,分布明显分离,是破碎波群区别于非破碎波群的显著指标;而其它各指标在破碎波群非破碎波群上的分布都有不同程度的交叠,不能单独依据它们区分破碎波群与非破碎波群。 相似文献
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In this paper experimental wind wave data are analyzed. It is found that differences in spectral width will give rise to differences in wave height distribution. The effect of spectral width on the distribution is mainly in the high wave range. The effect of wave steepness is in low, medium and high wave ranges. In the high wave range the effect of spectral width is comparable to that of wave steepness. Differences in spectral width in the observations may give rise to discrepancies in the result when wave steepness is the only parameter in the distribution. 相似文献
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