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INVESTIGATION OF LARGE-SCALE STRUCTURES IN WALL TURBULENCE

Ivan Marusic
Department of Mechanical Engineering, The University of Melbourne, Melbourne, VIC, 3010, Australia

Bharath Ganapathisubramani
Department of Aerospace Engineering and Mechanics, University of Minnesota 107 Akerman Hall, 110 Union Street SE, Minneapolis, MN 55455, USA; Department of Aeronautics, Imperial College London, Prince Consort Road, London, SW7 2AZ

Ellen K. Longmire
Department of Aerospace Engineering and Mechanics, University of Minnesota, 110 Union Street SE, Minneapolis, MN 55455, USA

A.K.M. Uddin
Aerospace Engineering and Mechanics University of Minnesota Minneapolis, MN 55455, USA

Sinopsis

In this paper an experimental and theoretical investigation is presented on the role of large-scale coherent structures in the zero-pressure-gradient turbulent boundary layer. Attention is given to the proposal by Adrian, Meinhart & Tomkins (2000) that hairpin vortices are organized into spatially correlated packets or trains of vortices which extend over many boundary layer thicknesses in the streamwise direction. Support for this scenario is given here from calculations using the attached eddy model of wall turbulence of Perry & Marusic (1995). Comparisons between calculation and experiment of structure angles and two-point velocity correlations indicate that spatially coherent packets are important at least in the region of the layer where the logarithmic law of the wall applies. Preliminary experimental results are also shown of stereo-PIV measurements in the spanwise-streamwise plane of a turbulent boundary layer.