Investigation of Structures of a Turbulent Spot in a Laminar Boundary Layer using Multiplane Stereo PIV

Abstract

An investigation of the development of an artificially induced turbulent spot in a laminar boundary layer by means of the Multiplane Stereo PIV technique at a low turbulence wind tunnel has been performed. Besides ensemble-averages of instantaneous velocity vectorfields and their corresponding rms-fields, the coherent structures and sub-structures of the spot was the focus of this examination. The calculation of the y-vorticity fields, PDF’s and space-time-correlations of the velocity fluctuation components and the Reynolds stresses at different wall distances leads to model of a spatial and temporal constellation of vortex structures inside such a turbulent spot.