Delta wing vortex control via recessed angled spanwise blowing

A novel vortex control technique, known as recessed angled span wise blowing, has been investigated in a water tunnel on a beveled 60-deg delta wing. Three pairs of blowing ports, located on the suction side of the wing and beneath the vortex core, were canted upward in the spanwise direction such that the injected flow is parallel to the beveled edge. Flow visualization experiments were performed using dye injected into the leadingedge vortices near the wing apex with the vortex burst location visually observed. Blowing coefficient values up to 0.1 were used in the experiments, although the effectiveness of blowing at a single chord location remained the same above blowing coefficients of 0.05. Maximum improvement in vortex breakdown location of 15% chord was obtained at an angle of attack of 22 deg and blowing coefficient of 0.05. Blowing from a port downstream of the natural burst location delayed vortex breakdown, whereas blowing upstream of the natural burst prompted vortex breakdown at the blowing port. Blowing ports at 41 % chord had the greatest effect in delaying vortex breakdown. These observations are explained via Rayleigh's stability criterion for circular flow.