On steep gravity waves meeting a vertical wall: a triple instability
On steep gravity waves meeting a vertical wall: a triple instability
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陡峭的重力波遇到垂直的墙壁：三重不稳定性
DOI：
10.1017/s0022112002001246
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发表时间：
2002
影响因子：
3.7
通讯作者：
M. Longuet
中科院分区：
文献类型：
--
作者：
David A. Drazen;M. Longuet
理论论证表明，只有当入射波的陡度ak很小，肯定小于0.284时，入射在垂直壁上的前进重力波才能产生周期性驻波。进行了实验室实验，其中入射波列的几乎均匀的振幅遇到一个垂直的障碍。当波陡大于0.236时，屏障附近产生的运动是非周期性的。观察到越来越多的不稳定性，其中每三个波峰都比其相邻的波峰陡峭。陡峭的波浪形成了尖锐的波峰，或垂直的急流。两个相邻的峰是圆形的，在顶部，或中间形式。每三个波周期，不稳定性增长约2.2倍，几乎与入射波陡度无关。
Theoretical arguments suggest that progressive gravity waves incident on a vertical wall can produce periodic standing waves only if the incident wave steepness ak is quite small, certainly less than 0.284. Laboratory experiments are carried out in which an incident wave train of almost uniform amplitude meets a vertical barrier. At wave steepnesses greater than 0.236 the resulting motion near the barrier is non-periodic. A growing instability is observed in which every third wave crest is steeper than its neighbours. The steep waves develop sharp crests, or vertical jets. The two neighbouring crests are rounded, at-topped, or of intermediate form. The instability grows by a factor of about 2.2 for every three wave periods, almost independently of the incident wave steepness.