Oscillation of Vortex Breakdown Location and Blowing Control of Time-Averaged Location

The goal of this research is the control of leading-edge vortex breakdown location utilizing along-the-core blowing near the apex on the leeward surface of sharp-edged, slender, delta wings at high angles of attack. In the S2Ch subsonic wind tunnel at ONERA Chalais Meudon, two delta wing models with 70-deg sweep angles and root chords of 950 mm have been configured to collect qualitative and quantitative surface and flowfield data. First, an examination of the streamwise, time-dependent oscillation of the leading-edge vortex breakdown locations without active flow control is presented. These results further the understanding of the vortex breakdown phenomena and provide a more precise basis for evaluating the effectiveness of various flow control methods. Second, open-loop blowing along one of the vortex cores on the leeward surface of the delta wing demonstrates the ability to displace downstream the controlled, time-averaged, vortex breakdown location by 20% of the root chord.