Prandtl-Blasius temperature and velocity boundary layer profiles in turbulent Rayleigh-Benard convection

ORAL

Abstract

The shapes of the velocity and temperature profiles near the horizontal conducting plates' center regions in turbulent Rayleigh-Benard convection are studied numerically and experimentally over the Rayleigh number range spanning from 10$^8$ to 3x10$^{11}$ and the Prandtl number range 0.7$\sim $5.4. The results show that both the temperature and velocity profiles well agree with the classical Prandtl-Blasius laminar boundary-layer profiles, if they are re-sampled in the respective dynamical reference frames that fluctuate with the instantaneous thermal and velocity boundary-layer thicknesses. The study further shows that the Prandtl-Blasius boundary layer in turbulent thermal convection not only holds in a time-averaged sense, but is also valid in an instantaneous sense most of the time.

*Work supported by the Research Grants Council of Hong Kong SAR (Project No. CUHK 403807).

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Authors

  • Ke-Qing Xia

    • The Chinese University of Hong Kong
    • The Chinese Univesity of Hong Kong

  • Quan Zhou

    • Shanghai University

  • Richard Stevens

    • University of Twente
    • University Twente

  • Kazuyasu Sugiyama

    • The Univ. of Tokyo
    • The University of Tokyo
    • Department of Mechanical Engineering, University of Tokyo
    • University of Tokyo

  • Siegfried Grossmann

    • Philipps-Universit\"at Marburg

  • Detlef Lohse

    • The University of Twente
    • University of Twente
    • Physics of Fluids group, University of Twente
    • Physics of Fluids, Twente University, The Netherlands
    • University of Twente, The Netherlands
    • Physics of Fluids, University of Twente
    • Physics of Fluids Group, University of Twente