NONLINEAR VORTEX FLOW-CONTROL FOR HIGH-ANGLE-OF-ATTACK MANEUVERING

The research covered in this paper explores the feasibility of expanding the flight envelope of a modified VISTA F-16 to higher angles-of-attack through forebody vortex flow control. The forebody vortex system is controlled with a pneumatic (blowing) forebody control system. The vortex blowing system is driven by nonlinear control laws that are derived using Variable Structure Control and describing function techniques. Nominal stability, robust stability, limit cycle, and nonlinear performance analyses are performed to examine control system performance. Results reveal that additional yaw control power from the blowing control system provides significant improvement in high-a performance.