Estimating ocean wave directional spreading from an Eulerian surface elevation time history
Estimating ocean wave directional spreading from an Eulerian surface elevation time history
复制标题
从欧拉表面高程时间历史估计海浪定向传播
DOI：
10.1098/rspa.2009.0031
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
P. Taylor
中科院分区：
文献类型：
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作者：
T. Adcock;P. Taylor
海况的定向扩展是海洋工程中的重要设计参数。波浪方向性影响所产生的波浪运动学，从而影响施加在海上结构上的力。在本文中，我们开发了一种估计扩散量的方法，当唯一可用的信息是空间中单个点的自由表面高程的时间历史时。我们通过预测在两个自由传播波的频率差处出现的二阶束缚波来做到这一点。这些二阶束缚波的幅度是相互作用波之间角度的函数。因此，可以从单点时间历史推断一些有关传播的信息。我们证明这种方法适用于完全非线性数值波池中的波群。我们创建了一个合成的随机海况并将噪声引入分析中，从而表明我们的方法是稳健的并且对噪声不敏感，即使在差异波中信噪比一致的情况下也是如此。这种方法也适用于直接测量扩散的物理波池中的随机波，也适用于北海记录的风暴。在所有情况下，我们发现我们对传播的估计与其他测量结果非常一致。
The directional spreading of sea states is an important design parameter in offshore engineering. Wave directionality affects the resulting wave kinematics, which affects the forces exerted on offshore structures. In this paper, we develop a method for estimating the amount of spreading, when the only information available is the time history of free surface elevation at a single point in space. We do this by predicting the second-order bound waves that occur at the difference in frequency of two freely propagating waves. The magnitude of these second-order bound waves is a function of the angle between the interacting waves. Thus, it is possible to infer some information about spreading from a single-point time history. We demonstrate that this approach works for wave groups in a fully nonlinear numerical wave tank. We create a synthetic random sea state and introduce noise into the analysis and thus show that our approach is robust and insensitive to noise, even with a signal-to-noise ratio of unity in the difference waves. This approach is also applied to random waves in a physical wave tank where spreading was directly measured and also to a storm recorded in the North Sea. In all cases, we find our estimate of spreading is in good agreement with other measurements.