Large scale organization of near wall turbulent boundary layer

etc15 Tracking Number 26

An experimental database at a Reynolds number based on momentum thickness Re close to 9800, was obtained in the Laboratoire de Mécanique de Lille wind tunnel with stereo-PIV (SPIV) and hot wire anemometry (HWA). With a Linear Stochastic Estimation procedure based on correlations computation, a 3 component field is reconstructed at high frequency from stereo-PIV at 4Hz and hot wire data at 30kHz. This paper describes methods for extracting large scale coherent structures (streaks and vortices) from the reconstructed PIV field. The outcoming features are characterized (size, intensity and life time), and the results are discussed with emphasis on the origin of the structures, their spatio-temporal organization and energetic contribution to the flow.