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Numerical estimation of wave spectra around an island by using wave diffraction theory

利用波衍射理论数值估计岛屿周围的波谱

基本信息

批准号：
15360267
负责人：
YOSHIDA Akinori
金额：
$ 4.42万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15360267/
关键词：
Islands Water Wave Diffraction Wave Spectrum Frequency Spectrum Directional Spectrum Wave Observation Boundary Element Method Wave distribution Function 島陰部係留浮体

项目摘要

We have developed a numerical method to predict water wave spectra at arbitrary points on the sea around an island. The method is based on numerical prediction of the wave field around the island. The wave field is obtained by using known wave diffraction theory on a cylindrical structure of arbitrary cross section in the sea of constant depth. The feature of the method lies in its simplicity in the prediction of wave spectra at any points in comparison with the prediction obtained through field observation.In this research, the calculation of wave field was first conducted using a boundary element method (BEM). The problems to be taken into consideration in numerical calculations were first investigated. Then, using obtained wave diffractions around the island, wave spectra (directional spectra and frequency spectra) were calculated. Along with the numerical prediction, field observation of waves around an specific island (Shirashima oil storage island, Kitakyushu, Fukuoka, Japan) was carried out from Oct. 2003 to Feb. 2004, and wave spectra were calculated from the obtained wave data. The numerically predicted spectra using the present method were compared with those obtained from field observation. It was confirmed that the effect of scattered waves reaches far from the islands and thus this should be considered in the estimation of incident wave spectra through field observation, and that the present method can give good overall prediction for the wave spectra at arbitrary points around islands.

我们已经开发了一种数值方法来预测海浪谱在任意点的海上岛屿周围。该方法是基于数值预报的波浪场周围的岛屿。利用已知的波浪绕射理论，得到了等深海中任意截面圆柱形结构物上的波浪场。该方法的特点是，与现场观测相比，可以简单地预测任意点的波浪谱。首先研究了数值计算中应考虑的问题。然后，使用所获得的波浪绕射周围的岛屿，波浪谱（方向谱和频谱）的计算。沿着数值预报，于2003年10月至2004年2月对日本福冈市北九州市白岛储油岛周围的波浪进行了现场观测，并根据观测数据计算了波浪谱。用本方法计算的光谱与野外观测的光谱进行了比较。结果表明，散射波的影响距离岛屿较远，在通过现场观测估算入射波谱时应考虑散射波的影响，该方法能较好地全面预测岛屿周围任意点的波谱。