ABSTRACT In coastal engineering, as shoaling waves break in shallow water, most wave-breaking research has been focused on depth-induced wave breaking. However, violent wave breaking under storm conditions may be caused by superposition of many shoaling wave components. In order for simulating extreme waves in open ocean, theories to focus wave-packets, assuming that wave speed of each wave component is unchanged during propagation (i.e. deep water or shallower water without bathymetry changes), have been derived, while shoaling effects of the focusing process in shallower waters have not been considered in the previous studies. The extension to shoaling coastal wave-packets may aid in simulating extreme coastal wave breaking under violent storm conditions via laboratory experiments. Here, we derive the general wave-packet focusing conditions for arbitrary water depth. The proposed conditions were used to simulate shoaling wave-packet focusing on flat and sloped bottoms in shallow water experiments for validation purposes. The effects of depth-induced wave breaking in the focusing wave groups are discussed in this paper. The current focusing technique can fully control the focus location and time in wave experiments with an arbitrary bottom structure, which may be useful for further extreme wave research in coastal engineering.

中文翻译：

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在浅水中聚焦的波包

摘要 在海岸工程中，由于浅水区的浅海破浪，大多数破浪研究都集中在深度诱发的破浪上。然而，风暴条件下的猛烈破浪可能是由许多浅滩波分量叠加造成的。为了模拟开阔海洋中的极端波浪，已经推导出聚焦波包的理论，假设每个波浪分量的波速在传播过程中保持不变（即深水或浅水没有水深变化），而浅滩效应以前的研究没有考虑过浅水区的聚焦过程。浅滩海岸波包的扩展可能有助于通过实验室实验模拟猛烈风暴条件下的极端沿海波浪破碎。这里，我们推导出任意水深的一般波包聚焦条件。所提出的条件用于模拟浅水实验中聚焦于平坦和倾斜底部的浅滩波包以进行验证。本文讨论了深度诱导波破碎在聚焦波群中的影响。目前的聚焦技术可以在任意底部结构的波浪实验中完全控制聚焦位置和时间，这可能有助于沿海工程中进一步的极端波浪研究。