The axial coherence of Kelvin–Helmholtz billows
The axial coherence of Kelvin–Helmholtz billows
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开尔文-亥姆霍兹波涛的轴向相干性
DOI：
10.1002/qj.200212858307
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发表时间：
2002
影响因子：
8.9
通讯作者：
By R. S. Thorpe
中科院分区：
文献类型：
--
作者：
By R. S. Thorpe
讨论了影响开尔文-亥姆霍兹波沿轴相干长度的因素。人们对决定或限制这一长度的过程知之甚少。实验室实验表明，随着波浪的发展，波浪可能会不规则地间隔，导致沿其长度成对，或者更常见的情况是，以不同的速度在斑块中生长，然后合并。这两个过程都导致了被描述为“结”的特征，即相邻的巨浪汇合在一起。波浪漩涡在结中的缠绕导致局部湍流和混合，通常在湍流在巨浪内部以较小的尺度发展之前。波浪的轴向相干长度受限于这些节点之间的轴向距离。尽管大气和海洋中的这些特征可能会对晴空湍流以及热量和动量输送产生影响，但它们几乎没有受到关注。对大气巨浪的观测表明，其轴向相干长度与实验室中发现的相同数量级，约为四个巨浪波长。版权所有(C)2002皇家气象学会。
Factors affecting the along‐axis coherence length of Kelvin–Helmholtz billows are reviewed. Little is known of the processes which determine or limit this length. Laboratory experiments show that, as they develop, billows may be irregularly spaced, resulting in pairing along their length, or, more commonly, grow at different rates in patches which subsequently amalgamate. Both processes result in features described as ‘knots’, where neighbouring billows join. The tangling of billow vortices in the knots leads to local turbulence and mixing, often before turbulence develops at a smaller scale within the billows themselves. The axial coherence length of billows is limited to the along‐axis distance between these knots. Such features in the atmosphere and the ocean have received little attention in spite of their possible bearing on clear‐air turbulence and to heat and momentum transport. Observations of atmospheric billows suggest an axial coherence length which is of the same order as that found in the laboratory, about four billow wavelengths. Copyright © 2002 Royal Meteorological Society.