Wall turbulence organization in the fully rough, very-high-<i>Re </i>logarithmic layer

ORAL

Abstract

We present super-large-scale particle image velocimetry (SLPIV) measurements in the thermally-neutral atmospheric surface layer. The field site represents a canonical fully rough wall boundary layer with a Reynolds number of the order Reτ∼106. The measurements capture the lowest 20 m of the surface layer and include the bottom of the logarithmic region. Structural features of the boundary layer observed in previous laboratory PIV studies are similarly present in our results at the atmospheric scale. We use the spatio-temporal SLPIV data to describe the spatial organization of wall turbulence in terms of vortex structures, zones of uniform momentum (UMZs), and internal shear layers. We compare the properties and wall-normal trends of these features to the characteristic scales of the logarithmic region, namely the friction velocity and the wall-normal distance. We discuss the findings in the context of existing theory such as the attached eddy hypothesis.

*This work is supported by the Institute on the Environment and the National Science Foundation.

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Presenters

  • Michael Heisel

    • University of Minnesota, St. Anthony Falls Laboratory
    • Univ of Minnesota - Twin Cities

Authors

  • Michael Heisel

    • University of Minnesota, St. Anthony Falls Laboratory
    • Univ of Minnesota - Twin Cities

  • Jiarong Hong

    • Department of Mechanical Engineering & Saint Anthony Falls Laboratory, University of Minnesota
    • University of Minnesota
    • University of Minnesota, St. Anthony Falls Laboratory
    • University of Minnesota - Twin Cities, Saint Anthony Falls Laboratory
    • Univ of Minnesota - Twin Cities

  • Filippo Coletti

    • University of Minnesota
    • Univ of Minnesota - Twin Cities
    • University of Minnesota, St. Anthony Falls Laboratory
    • University of Minnesota - Twin Cities
    • University of Minnesota, Twin Cities

  • Michele Guala

    • University of Minnesota, Twin Cities
    • University of Minnesota, St. Anthony Falls Laboratory
    • Univ of Minn - Minneapolis
    • University of Minnesota