Experimental properties of continuously forced, shear-driven, stratified turbulence. Part 2. Energetics, anisotropy, parameterisation
Experimental properties of continuously forced, shear-driven, stratified turbulence. Part 2. Energetics, anisotropy, parameterisation
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连续受力、剪切驱动、分层湍流的实验特性。
DOI：
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发表时间：
2021
影响因子：
3.7
通讯作者：
P. Linden
中科院分区：
文献类型：
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作者：
A. Lefauve;P. Linden
摘要 在第二部分中，我们进一步研究了分层倾斜管道中两层交换流的实验特性，这些交换流是湍流、强分层、剪切驱动和连续受力的。我们使用与第 1 部分相同的“核心”剪切层方法分析相同的最先进数据集（Lefauve & Linden, J. Fluid Mech., vol. 937, 2022, A34），但我们在这里重点关注湍流能量学和混合统计。对动能和标量能量收支的详细分析揭示了“SID 湍流”的特异性和尺度，而能谱则让我们深入了解当前实验数据的优势和局限性。不同尺度下流动的各向异性表征了Holmboe波和翻转湍流的湍流动能产生和耗散机制。然后，我们根据均匀涡流扩散率、混合长度、通量参数、浮力雷诺数或湍流弗劳德数评估标准混合参数化模型，并将我们的代表值与分层混合文献进行比较。还阐明了这些混合测量对可控流动参数的依赖性，提供了可以外推到更强烈的湍流的渐近估计，通过管道的倾斜角和雷诺数的乘积来量化。这些见解可以作为下一代实验数据的基准，这些数据具有探测日益剧烈的湍流所需的卓越时空分辨率。
Abstract In this Part 2 we study further experimental properties of two-layer exchange flows in a stratified inclined duct, which are turbulent, strongly stratified, shear-driven and continuously forced. We analyse the same state-of-the-art data sets using the same ‘core’ shear-layer methodology as in Part 1 (Lefauve & Linden, J. Fluid Mech., vol. 937, 2022, A34), but we focus here on turbulent energetics and mixing statistics. The detailed analysis of kinetic and scalar energy budgets reveals the specificity and scalings of ‘SID turbulence’, while energy spectra provide insight into the current strengths and limitations of our experimental data. The anisotropy of the flow at different scales characterises the turbulent kinetic energy production and dissipation mechanisms of Holmboe waves and overturning turbulence. We then assess standard mixing parameterisation models relying on uniform eddy diffusivities, mixing lengths, flux parameters, buoyancy Reynolds numbers or turbulent Froude numbers, and we compare our representative values with the stratified mixing literature. The dependence of these measures of mixing on controllable flow parameters is also elucidated, providing asymptotic estimates that may be extrapolated to more strongly turbulent flows, quantified by the product of the tilt angle of the duct and the Reynolds number. These insights may serve as benchmark for the future generation of experimental data with superior spatio-temporal resolution required to probe increasingly vigorous turbulence.
湍流分层混合中的开放性问题：我们是否知道我们不知道的东西？
影响因子：
2.7
作者：
Caulfield C
通讯作者：
Caulfield C