共查询到10条相似文献，搜索用时 62 毫秒
1.
《Ocean Engineering》1999,26(2):161-188
The directionality of waves inside a groin field near the German coastal zone of the island of Norderney is studied in the frequency domain. The maximum entropy method is adopted to estimate the directional spreading function. The various characteristics of the directional distribution of waves have been presented for the locations both inside and outside the groin field. The variation of directional spreading with depth and the importance of study of directional waves in coastal regions are discussed. 相似文献
2.
A spatial array of wave gauges installed on an observatoion platform has been designed and arranged to measure the lo-cal features of winter monsoon directional waves off Taishi coast of Taiwan. A new method, named the Bayesian Parameter Estimation Method(BPEM) , is developed and adopted to determine the main direction and the directional spreading parame-ter of directional spectra. The BPEM could be considered as a regression analysis to find the maximum joint probability of parameters, which best approximates the observed data from the Bayesian viewpoint. The result of the analysis of field wave data demonstrates the highly dependency of the characteristics of normalized directional spreading on the wave age. The Mit-suyasu type empirical formula of directional spectrum is therefore modified to be representative of monsoon wave field. More-over, it is suggested that Smax could be expressed as a function of wave steepness. The values of Smax decrease with increas-ing steepness. Finally, a local directi 相似文献
3.
海浪双峰方向分布的一种物理解释 总被引：3，自引：0，他引：3
用 １８个波高计组成的直径为 ４０ｃｍ的圆形阵列在大型风浪槽内系统地测量了风浪和涌浪方向谱。用两种分辨力较高的方向谱估计方法最大似然法（ＭＬＭ）和贝叶斯方法（ＢＤＭ）分析的结果表明：风浪高频域出现的依赖于估计方法的双峰方向分布是一种物理假象;在较成长的涌浪低频域,得到跟传播方向对称、两峰间隔大约６０°－９０°非常规则的双峰方向分布,它跟频率和涌浪的成长状态有关,而跟估计方法无关,这种现象可以用非线性波－波相互作用过弱,在不同方向之间不能有效传递能量来解释。 相似文献
4.
The performance of various directional instruments for practical oceanographic and coastal engineering applications is examined. The emphasis is put on the application of conventional current meters equipped with high resolution pressure sensors and three element arrays. Two simulation techniques have been used to produce input data with known frequency spectrum and known directional spreading. The directional spreading is determined by the maximum likelihood method and the resulting spreading is compared with the input spreading. The performance of a conventional current meter equipped with a high resolution pressure sensor depends on the width of the directional spreading of surface waves and on the frequencies under consideration. Even for very narrow directional spreading, the current meter response is acceptable for practical applications and for shallow water deployment. In general, the current meter directional response does not depend on the direction of the incident waves. The spatial array of three wave staffs deployed in shallow water shows a similar performance to that of the current meters when the dimension of the spatial array is of the order of 1 m. This performance also does not depend on the direction of the incident waves. 相似文献
5.
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
6.
Yu Yuxiu Liu Shuxue Prof 《中国海洋工程》1992,(2)
- Measuring multi-directional waves with the wave gauge array is one of the fundamental and easily realised methods. In this paper, the wave gauge array is described and the effects of the gauge spacing, the array orientations, etc. of the three array arrangements, i. e., linear array, T-type array and pentagon array, on the resolution of the directional spreading of waves, are investigated experimentally. This study can be used as a reference in the experimental study and the field measurement of directional waves. 相似文献
7.
Liu Shuxue Yu Yuxiu
Assistant Researcher State Key Laboratory of Coastal Offshore Engineering Dalian University of Technology 《中国海洋工程》1995,(1)
The directional spectrum is one of the basic characteristics of sea waves. The observations of directional spectrum of sea waves were successfully conducted at platform Bohai 8 during 1991 and 1992 using a wave gage array for the first time in China. Based on the field data, the directional spectrum which depends on the wave growth is given in this paper. Before observations, the effects of the type of gage array, the distance between the gages and the platform itself on the measured results and the precision of some methods for estimating the directional spectrum were investigated and compared with the methods of numerical simulations and model tests of multi-direcitonal irregular waves. This ensures the quality of the observations and estimations of the directional spectrum. 相似文献
8.
《中国海洋工程》2021,(4)
The main objective of this paper is to examine the influences of both the principal wave direction and the directional spreading parameter of the wave energy on the wave height evolution of multidirectional irregular waves over an impermeable sloping bottom and to propose an improved wave height distribution model based on an existing classical formula. The numerical model FUNWAVE 2.0, based on a fully nonlinear Boussinesq equation, is employed to simulate the propagation of multidirectional irregular waves over the sloping bottom. Comparisons of wave heights derived from wave trains with various principal wave directions and different directional spreading parameters are conducted. Results show that both the principal wave direction and the wave directional spread have significant influences on the wave height evolution on a varying coastal topography. The shoaling effect for the wave height is obviously weakened with the increase of the principal wave direction and with the decrease of the directional spreading parameter. With the simulated data, the classical Klopman wave height distribution model is improved by considering the influences of both factors. It is found that the improved model performs better in describing the wave height distribution for the multidirectional irregular waves in shallow water. 相似文献
9.
海浪方向谱的现场观测与分析 总被引：3，自引：0，他引：3
方向谱是海浪的基本性质之一。本文在国内首次采用测波仪阵列法在渤海采油平台上成功地观测到海浪方向谱，给出了当地随波浪成长而变化的方向谱表达式。观测前采用数模和模型试验方法，对阵列的布置型式、测波仪间距和平台等对观测结果的影响，以及现有各种方向谱分析方法的精度等进行了对比分析，为提高观测精度，保证方向谱分析的质量提供了依据。 相似文献
10.
The directional spreading of both the wavenumber and frequency spectra of finite-depth wind generated waves at the asymptotic depth limit are examined. The analysis uses the Wavelet Directional Method, removing the need to assume a form for the dispersion relationship. The paper shows that both the wavenumber and frequency forms are narrowest at the spectral peak and broaden at wavenumbers (frequencies) both above and below the peak. The directional spreading of the wavenumber spectrum is bi-modal above the spectral peak. In contrast, the frequency spectrum is uni-modal. This difference is shown to be the result of energy in the wind direction being displaced from the linear dispersion shell. A full parametric relationship for the directional spreading of the wavenumber spectrum is developed. The analysis clearly shows that typical dispersion relationships are questionable at high frequencies and that such effects can be significant. This result supports greater attention being focussed on the routine recording of wavenumber spectra, rather than frequency spectra. 相似文献