Flow reversals in thermally driven turbulence

Kazuyasu Sugiyama, Rui Ni, Richard J.A.M. Stevens, Tak Shing Chan, Sheng Qi Zhou, Heng Dong Xi, Chao Sun, Siegfried Grossmann, Ke Qing Xia, Detlef Lohse

Research output: Contribution to journalArticle

105 Scopus citations

Abstract

We analyze the reversals of the large-scale flow in Rayleigh-Bénard convection both through particle image velocimetry flow visualization and direct numerical simulations of the underlying Boussinesq equations in a (quasi-) two-dimensional, rectangular geometry of aspect ratio 1. For medium Prandtl number there is a diagonal large-scale convection roll and two smaller secondary rolls in the two remaining corners diagonally opposing each other. These corner-flow rolls play a crucial role for the large-scale wind reversal: They grow in kinetic energy and thus also in size thanks to plume detachments from the boundary layers up to the time that they take over the main, large-scale diagonal flow, thus leading to reversal. The Rayleigh vs Prandtl number space is mapped out. The occurrence of reversals sensitively depends on these parameters.

Original languageEnglish (US)
Article number034503
JournalPhysical Review Letters
Volume105
Issue number3
DOIs
StatePublished - Jul 16 2010

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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    Sugiyama, K., Ni, R., Stevens, R. J. A. M., Chan, T. S., Zhou, S. Q., Xi, H. D., Sun, C., Grossmann, S., Xia, K. Q., & Lohse, D. (2010). Flow reversals in thermally driven turbulence. Physical Review Letters, 105(3), [034503]. https://doi.org/10.1103/PhysRevLett.105.034503