High Angle of Attack Aerodynamics

Abstract In this chapter, low‐speed aerodynamics of highly swept wings is discussed. Highly swept wings, known asdeltawings, can fly at high angle of attack without stall. This quality is invaluable for military aircraft during a high angle of attack maneuver. Leading‐edge vortices develop on highly swept wings as a result of flow separation and contribute to the lift force. Highly energetic vortices break down or burst at high angles of attack, resulting in highly unsteady flows. Vortex breakdown may cause wing or fin vibrations, called buffeting, which is the structural response due to the unsteady flow. Aircraft configurations may have forebody vortices, leading‐edge vortices that originate from strakes, and the main wing vortices, which may interact with each other during a maneuver. Leading‐edge vortices in unsteady flows exhibit substantial time lag and hysteresis effects. They may also cause self‐induced roll oscillations of aircraft, known as wing rock. Finally, vortex control techniques are briefly discussed.