Long–wave forcing by the breaking of random gravity waves on a beach
Long–wave forcing by the breaking of random gravity waves on a beach
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DOI：
10.1098/rspa.2002.0962
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发表时间：
2002-09
期刊：
影响因子：
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通讯作者：
T. Baldock;D. Huntley
中科院分区：
文献类型：
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作者：
T. Baldock;D. Huntley
本文介绍了在平面海滩上由较短重力水波随机破碎引起的长波（浪拍）强迫的新的实验室数据。这些数据包括入射波和出射波振幅，以及长波频率下的海岸线振荡振幅，由此检验了强迫长波和短波群之间的相关性。对长波运动的跨岸结构进行了详细的分析，并与现有的二维浪拍生成理论进行了严格的比较。冲浪拍表现出对标准化冲浪区宽度的强烈依赖，与时变断点引起的长波强迫相一致，对于考虑的随机波模拟，几乎没有证据表明入射束缚长波的释放和反射。向海传播长波与入射短波群呈正相关，与短波幅值呈线性关系。入射束缚长波与辐射自由长波的相位关系也符合断点强迫。结合以往的工作，目前的数据表明，在陡入射短波条件下，断点变率可能是主要的强迫机制。
This paper presents new laboratory data on long–wave (surf–beat) forcing by the random breaking of shorter gravity water waves on a plane beach. The data include incident and outgoing wave amplitudes, together with shoreline oscillation amplitudes at long–wave frequencies, from which the correlation between forced long waves and short–wave groups is examined. A detailed analysis of the cross–shore structure of the long–wave motion is presented, and the observations are critically compared with existing theories for two–dimensional surf–beat generation. The surf beat shows a strong dependency on normalized surf–zone width, consistent with long–wave forcing by a time–varying breakpoint, with little evidence of the release and reflection of incident bound long waves for the random–wave simulations considered. The seaward–propagating long waves show a positive correlation with incident short–wave groups and are linearly dependent on short–wave amplitude. The phase relationship between the incident bound long waves and radiated free long waves is also consistent with breakpoint forcing. In combination with previous work, the present data suggest that the breakpoint variability may be the dominant forcing mechanism during conditions with steep incident short waves.