Classical 1/3 scaling of convection holds up to Ra = 1015

Kartik P. Iyer, Janet D. Scheel, Jörg Schumacher, Katepalli R. Sreenivasan

Research output: Contribution to journalArticlepeer-review

Abstract

The global transport of heat and momentum in turbulent convection is constrained by thin thermal and viscous boundary layers at the heated and cooled boundaries of the system. This bottleneck is thought to be lifted once the boundary layers themselves become fully turbulent at very high values of the Rayleigh number Ra-the dimensionless parameter that describes the vigor of convective turbulence. Laboratory experiments in cylindrical cells for Ra & 1012 have reported different outcomes on the putative heat transport law. Here we show, by direct numerical simulations of three-dimensional turbulent Rayleigh-Bénard convection flows in a slender cylindrical cell of aspect ratio 1/10, that the Nusselt number-the dimensionless measure of heat transport-follows the classical power law of Nu = (0.0525 ± 0.006) × Ra0.331+0.002 up to Ra = 1015. Intermittent fluctuations in the wall stress, a blueprint of turbulence in the vicinity of the boundaries, manifest at all Ra considered here, increasing with increasing Ra, and suggest that an abrupt transition of the boundary layer to turbulence does not take place.

Original languageEnglish (US)
Pages (from-to)7594-7598
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume117
Issue number14
DOIs
StatePublished - Apr 7 2020

Keywords

  • Direct numerical simulation
  • Turbulent convection
  • Turbulent heat transfer

ASJC Scopus subject areas

  • General

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