| Vortex control techniques were developed to manage the steady asymmetric vortices produced by slender bodies of revolution at high angles of attack. The vortex control techniques used steady suction, steady blowing, and unsteady bleed applied through small control ports located at the tip of the forebody model. The vortex control techniques were capable of manipulating both the magnitude and direction of the side force generated by the asymmetric vortices.; Measurements of the distortion in the mean velocity profiles behind a forebody model provided conclusive evidence that a spatial instability of the forebody wake was responsible for the development of the vortex asymmetry. Placing the flow actuators at the model tip exploited the amplification characteristics of the spatial instability. As a result, control of the vortex configuration and the side force was achieved with very low forcing amplitudes and input power levels.; The flow actuators were incorporated into closed-loop control systems that employed feedback from the forebody vortices. The performance of linear and nonlinear control laws was studied and evaluated. For the pitching forebody models, the controllers were found to be most effective at angles of attack less than 50{dollar}spcirc.{dollar} The control system designed for the coning motion model was capable of controlling the yaw angle of the model, its rotation rate, and the direction of rotation. |
