The shape of large surface waves on the open sea and the Draupner New Year wave
The shape of large surface waves on the open sea and the Draupner New Year wave
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DOI：
10.1016/j.apor.2005.02.001
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发表时间：
2004-05-01
影响因子：
4.3
通讯作者：
Taylor, RE
中科院分区：
文献类型：
--
作者：
Walker, DAG;Taylor, PH;Taylor, RE
海洋表面波在时间上是随机的，同时也是非线性的。对于海面的线性随机模型，发现大波峰的平均形状是缩放自相关函数，如Lindgren [Lindgren G.正规过程在局部极大值附近的一些性质。Ann Math星星1970;41：1870-83]和Boccotti [Boccotti P.风浪统计特性的一些新结果。Appl Ocean Res 1983;5：134-40]。使用现场数据从北海，这个简单的结果的适用性进行了讨论。斯托克斯型校正五阶合并在一个近似的，但强大的方式，有效的至少在本地的空间和时间。精确的二阶波动理论被用来检查的近似斯托克斯处理的准确性，并澄清的大小和二阶的贡献的性质。本文对1995年1月1日15时20分在北海Draupner平台记录到的一次巨浪--新年浪进行了检验。在有效波高约为12 m的海况下，明确记录了峰值高于静水面18.5 m的异常波。使用Stokes模型去除该波的局部不对称性，从而基于线性波峰振幅的标准瑞利分布来估计该显著事件发生的概率。它的结论是，新的物理，不纳入标准的方法，海洋工程设计，可能发挥了重要作用，在产生这种畸形波。(c)2005爱思唯尔有限公司保留所有权利。
Ocean surface waves are both random in time and nonlinear. For a linear random model of the sea surface, the average shape of a large crest is found to be the scaled auto-correlation function, as is shown mathematically by Lindgren [Lindgren G. Some properties of a normal process near a local maximum. Ann Math Star 1970;41:1870-83] and Boccotti [Boccotti P. Some new results on statistical properties of wind waves. Appl Ocean Res 1983;5:134-40]. Using field data from the North Sea, the applicability of this simple result is discussed. Stokes-type corrections up to fifth order are incorporated in an approximate but robust manner, valid at least locally in space and time. Exact second-order wave theory is used to check the accuracy of the approximate Stokes treatment and to clarify the magnitude and character of the second-order contributions. A giant wave, called the New Year wave, recorded at the Draupner platform in the North Sea at 15:20 on 1st January 1995, is examined. In a sea-state with a significant wave height of approximately 12 m, this freak wave, which has a peak elevation of 18.5 m above still water level, was unambiguously recorded. The local asymmetries of this wave are removed using the Stokes model, allowing the probability of occurrence of this remarkable event to be estimated, based on the standard Rayleigh distribution for linear crest amplitude. It is concluded that new physics, not incorporated in standard approaches to offshore engineering design, may have played an important role in the generation of this freak wave. (c) 2005 Elsevier Ltd. All rights reserved.