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.

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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