Flow Reversals in Thermally Driven Turbulence

K. Sugiyama, Rui Ni, Richard Johannes Antonius Maria Stevens, Tak Shing Chan, Sheng-Qi Zhou, Heng-Dong Xi, Chao Sun, Siegfried Grossmann, K. Xia, Detlef Lohse

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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 languageUndefined
Pages (from-to)034503-1-034503-4
Number of pages4
JournalPhysical review letters
Volume105
Issue number3
DOIs
Publication statusPublished - 2010

Keywords

  • METIS-267332
  • IR-79180

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