Response of boundary layer flow to vortices normal to the leading edge

The response of a boundary layer at a plate with a blunt nose to steady vortices normal to the leading edge was studied experimentally, The wake behind a wire stretched normally to the plate was used as a source of vortical disturbances. Three regimes of wake/boundary layer interaction, distinguished by the distribution of spanwise disturbances and their downstream development were observed. In particulars the non-symmetric response of the boundary layer to a high velocity deficit symmetric wake has been discovered. It was shown that wake vorticity field deformation by die flow around the leading edge plays a decisive role in streamwise vortex formation above the boundary layer and boundary layer distortion. (C) 2001 Editions scientifiques et medicales Elsevier SAS.