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arXiv · 1706.09800

Extreme-scale motions in turbulent plane Couette flows

Myoungkyu Lee·Robert D. Moser
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Abstract

We study the size of large-scale motions in turbulent plane Couette flows at moderate Reynolds number up to $Re_τ$ = 500. Direct numerical simulation domains were as large as $100πδ\times2δ\times5πδ$, where $δ$ is half the distance between the walls. The results indicate that there are structures with streamwise extent, as measured by the wavelength, as long as 78$δ$ and at least 310$δ$ at $Re_τ$ = 220 and 500, respectively. The presence of these very long structures is apparent in the spectra of all three velocity components and the Reynolds stress. In DNS using a smaller domain, the large structures are constrained, eliminating the streamwise variations present in the larger domain. Effects of a smaller domain are also present in the mean velocity and the streamwise velocity variance in the outer flow.

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Myoungkyu Lee, Robert D. Moser. 2018-01-29. Extreme-scale motions in turbulent plane Couette flows. https://doi.org/10.1017/jfm.2018.131

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