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arXiv 1902.05313physics.flu-dyn
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准二维turbulence中的凝聚

Condensate in quasi two-dimensional turbulence

Stefano Musacchio, Guido Boffetta

摘要:

本文研究了限制在薄层中的湍流中大尺度结构的形成过程。通过对纳维-斯托克斯方程的直接数值模拟,在中等尺度下,我们得到了能量级联的分裂,其中一部分输入进入小尺度,产生三维直接级联。剩余的能量流向大尺度,产生逆级联,最终在最大水平尺度上形成准二维凝聚态。我们的研究结果表明,在薄层分裂能量级联的两个演员之间的连接比以前建立的更紧密:小尺度的三维湍流作为一个有效的粘度和耗散的大规模的能量,从而提供了一个粘度无关的机制,阻止冷凝物的增长。这种情况下支持的定量预测的饱和能在冷凝。

英文摘要:

We investigate the process of formation of large-scale structures in a turbulent flow confined in a thin layer. By means of direct numerical simulations of the Navier-Stokes equations, forced at an intermediate scale, we obtain a split of the energy cascade in which one fraction of the input goes to small scales generating the three-dimensional direct cascade. The remaining energy flows to large scales producing the inverse cascade which eventually causes the formation of a quasi two-dimensional condensed state at the largest horizontal scale. Our results shows that the connection between the two actors of the split energy cascade in thin layers is tighter than what was established before: the small scale three-dimensional turbulence acts as an effective viscosity and dissipates the large-scale energy thus providing a viscosity-independent mechanism for arresting the growth of the condensate. This scenario is supported by quantitative predictions of the saturation energy in the condensate.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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