Mixing in Symmetric Holmboe Waves
Mixing in Symmetric Holmboe Waves
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混合对称 Holmboe 波
DOI：
10.1175/jpo3037.1
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发表时间：
2007
影响因子：
3.5
通讯作者：
G. Lawrence
中科院分区：
文献类型：
--
作者：
W. Smyth;J. Carpenter;G. Lawrence
摘要用直接模拟方法研究了Holmboe波中的湍流和混合。以前的结果表明，Holmboe波的混合与更著名的Kelvin-Helmholtz(KH)波的混合相当，并扩展到覆盖一系列层结级别。详细讨论了混合效率以及浮力和动量的有效扩散系数。将夹带率与实验室实验结果进行了比较。结果表明，剪切层和层状层厚度之比是控制混合的关键参数。在这一比例保持不变的情况下，KH波的混合速度比Holmboe波更快。在Holmboe波中，混合随着密度差的增大而增加，尽管层结延迟或完全阻止了向湍流的转变。在Holmboe波的有效粘性和扩散系数的参数化中总结了结果。
Abstract Direct simulations are used to study turbulence and mixing in Holmboe waves. Previous results showing that mixing in Holmboe waves is comparable to that found in the better-known Kelvin–Helmholtz (KH) billows are extended to cover a range of stratification levels. Mixing efficiency is discussed in detail, as are effective diffusivities of buoyancy and momentum. Entrainment rates are compared with results from laboratory experiments. The results suggest that the ratio of the thicknesses of the shear layer and the stratified layer is a key parameter controlling mixing. With that ratio held constant, KH billows mix more rapidly than do Holmboe waves. Among Holmboe waves, mixing increases with increasing density difference, despite the fact that the transition to turbulence is delayed or prevented entirely by the stratification. Results are summarized in parameterizations of the effective viscosity and diffusivity of Holmboe waves.