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 vor tices normal to the leading edge was studied experimentally, The wake behin d a wire stretched normally to the plate was used as a source of vortical d isturbances. Three regimes of wake/boundary layer interaction, distinguishe d by the distribution of spanwise disturbances and their downstream develop ment were observed. In particulars the non-symmetric response of the bounda ry layer to a high velocity deficit symmetric wake has been discovered. It was shown that wake vorticity field deformation by die flow around the lead ing edge plays a decisive role in streamwise vortex formation above the bou ndary layer and boundary layer distortion. (C) 2001 Editions scientifiques et medicales Elsevier SAS.