SIDE-FORCE CONTROL ON A DIAMOND FOREBODY AT HIGH ANGLES OF ATTACK

A high-alpha side-force control concept for diamond cross section forebodies was investigated. A full-length strake is deployed on one of the lower facets to force a large-scale separation vortex adjacent to the forebody surface, whose suction provides side force across a broad high-alpha range. A simultaneous reduction of the leeside vortex suction decreases the forebody normal force, leading to pitch-up alleviation and drag reduction as additional high-alpha benefits, particularly when the strakes are deployed on both sides. Low-speed wind-tunnel measurements of surface pressures and six-component forces/moments supported by surface and flowfield visualizations on an isolated diamond forebody model verified the control effectiveness to nearly 70-deg angle of attack, and up to 10-deg sideslip angle.