Investigation of Large-scale Structures in Wall Turbulence
نویسندگان
چکیده
In this paper an experimental and theoretical investigation is presented on the role of large-scale coherent structures in the zeropressure-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 stereoPIV measurements in the spanwise-streamwise plane of a turbulent boundary layer.
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