Wave Transmission: Spectral Changes and Its Effects on Run-Up and Overtopping
Wave Transmission: Spectral Changes and Its Effects on Run-Up and Overtopping
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DOI：
10.1061/40549(276)168
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发表时间：
2001-03
影响因子：
4.4
通讯作者：
J. V. D. Meer;E. Regeling;J. D. Waal
中科院分区：
文献类型：
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作者：
J. V. D. Meer;E. Regeling;J. D. Waal
波浪在低顶结构物上传播的研究主要集中在确定波浪传播系数，即透射波高与入射波高的比值。很明显，这种结构降低了波高，但还有更多！Goda，Tanimoto等人，Raichlen等人和货车。der梅尔都得出结论，平均周期也减少到事件平均周期的0.4-1.0。结论是越浪会产生更多的波浪。此外，Raichlen等人和Lee给出了透射波的测量光谱的例子。这两个例子都显示了与入射光谱相似的光谱峰值，但在较高频率处具有更多的能量。对结构物前的波高进行良好的估计是设计或评估此类结构物所必需的。而且波浪周期和有时频谱形状也可能对设计产生影响。例如，波浪爬高在很大程度上取决于波浪的周期。为了确定可接受爬高所需的堤坝高度，应了解波高和周期。在这种堤坝前面的低顶结构提供一定保护的情况下，应研究波浪周期和频谱变化。在荷兰当地的情况是本文提出的研究的原因。图1给出了一个示意性布局。一个大湖位于西侧（图中左侧），西北风可能会产生超过2米的波浪。东侧的堤坝部分受到各种低顶结构或水坝系统的保护，包括一些开口。该图显示了对波穿透的计算结果。这些计算由Alkyon进行。低顶堤坝上除产生波浪穿透外，还产生波浪透射。面积约1公里乘2.5公里。这意味着，在极端条件下，当取风超过1 km时，也会出现本地生成的（短）波。堤前的波浪气候可以描述为波浪穿透、波浪传播和局部产生的风浪的组合。本文只讨论了波的传播，但最后讨论了对总波气候的影响。
Most research work on wave transmission over low-crested structures has been concentrated on establishing the wave transmission coefficient, i.e. the ratio between transmitted and incident significant wave height. It is clear that such structures decrease the wave height, but there is more! Goda, Tanimoto et al. Raichlen et al. and Van. der Meer all conclude that also the mean period reduces to 0.4–1.0 of the incident mean period. The conclusion is that overtopping generates more waves. Further, Raichlen et al. and Lee give examples of measured spectra of transmitted waves. Both examples show the peak of the spectrum similar to the incident spectrum, but with much more energy at the higher frequencies. A good estimation of the wave height in front of a structure is required for design or assessment of such a structure. But also wave period and sometimes spectral shape may have influence on the design. Wave run-up, for example, depends largely on the wave period. In order to establish the required dike height for acceptable run-up, both wave height and period should be known. In situations where a low-crested structure in front of such a dike gives some protection, wave period and spectral changes should be studied. A local situation in the Netherlands was the reason for the research presented in this paper. Figure 1 gives a schematised layout. A large lake is situated on the west side (left side in the figure) and NW wind may generate waves up to a significant wave height of over 2 m. The dikes on the eastern side are partly protected by a system of various low-crested structures or dams, including some openings. The figure shows the results of a calculation on wave penetration. Such calculations were performed by Alkyon. Besides wave penetration, wave transmission is generated over the low-crested dams. The area is about 1 km by 2.5 km. This means that with a fetch of more than 1 km also locally generated (short) waves will be present during extreme conditions. The wave climate in front of the dikes can be described as a combination of wave penetration, wave transmission and locally generated wind waves. This paper deals with wave transmission only, but the effect on the total wave climate is discussed at the end.