Biases in Thorpe-Scale Estimates of Turbulence Dissipation. Part II: Energetics Arguments and Turbulence Simulations
Biases in Thorpe-Scale Estimates of Turbulence Dissipation. Part II: Energetics Arguments and Turbulence Simulations
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DOI：
10.1175/jpo-d-14-0092.1
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发表时间：
2015-10
影响因子：
3.5
通讯作者：
A. Scotti
中科院分区：
文献类型：
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作者：
A. Scotti
AbstractThis本文使用的Scotti和白色开发的能量学框架提供了一个重要的评估广泛使用的索普尺度方法，这是用来估计耗散和混合率分层湍流密度测量沿着垂直剖面。这项研究表明，相关的位移尺度一般不是索普位移的均方根值。相反，位移场必须进行雷诺分解，以将平均值与湍流分量分离，并且应该使用湍流分量来诊断混合和耗散。一般来说，在整体稳定分层流中的混合能量学涉及与流的平均和湍流分量相关联的可用势能和动能之间的潜在复杂交换。作者认为两个极限情况：剪切驱动的混合，其中混合是在流动的平均动能为代价，和对流驱动的混合，其中水龙头的ava…
AbstractThis paper uses the energetics framework developed by Scotti and White to provide a critical assessment of the widely used Thorpe-scale method, which is used to estimate dissipation and mixing rates in stratified turbulent flows from density measurements along vertical profiles. This study shows that the relevant displacement scale in general is not the rms value of the Thorpe displacement. Rather, the displacement field must be Reynolds decomposed to separate the mean from the turbulent component, and it is the turbulent component that ought to be used to diagnose mixing and dissipation. In general, the energetics of mixing in an overall stably stratified flow involves potentially complex exchanges among the available potential energy and kinetic energy associated with the mean and turbulent components of the flow. The author considers two limiting cases: shear-driven mixing, where mixing comes at the expense of the mean kinetic energy of the flow, and convective-driven mixing, which taps the ava...