Baropycnal Work: A Mechanism for Energy Transfer across Scales
Baropycnal Work: A Mechanism for Energy Transfer across Scales
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DOI：
10.3390/fluids4020092
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发表时间：
2019-05
期刊：
影响因子：
1.9
通讯作者：
A. Lees;H. Aluie
中科院分区：
文献类型：
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作者：
A. Lees;H. Aluie
斜压性的作用是由压力梯度和密度梯度的错位引起的，它在涡度方程中是众所周知的，但它在动能收支中的作用从来就不明显。在这里，我们表明，斜压性自然出现在动能收支进行适当的尺度分解后。压力和密度梯度，正压和斜压的应变产生，也从我们的分析结果。这两个过程的基础上最近确定的机制，“压密功”，它可以转移能量跨尺度的变密度流。正因为如此，气压密度的工作是显着不同的压力膨胀，前者是隐式集中在大涡模拟。我们提供了1024 3可压缩湍流的直接数值模拟的数值证据。数据显示出良好的逐点协议之间的气压密度的工作和我们得到的非线性模型，支持我们的解释，它是如何运作的。
The role of baroclinicity, which arises from the misalignment of pressure and density gradients, is well-known in the vorticity equation, yet its role in the kinetic energy budget has never been obvious. Here, we show that baroclinicity appears naturally in the kinetic energy budget after carrying out the appropriate scale decomposition. Strain generation by pressure and density gradients, both barotropic and baroclinic, also results from our analysis. These two processes underlie the recently identified mechanism of “baropycnal work”, which can transfer energy across scales in variable density flows. As such, baropycnal work is markedly distinct from pressure-dilatation into which the former is implicitly lumped in Large Eddy Simulations. We provide numerical evidence from 1024 3 direct numerical simulations of compressible turbulence. The data shows excellent pointwise agreement between baropycnal work and the nonlinear model we derive, supporting our interpretation of how it operates.