Model-based feedback flow control development and simulation for a pitching turret

Closed-loop systems have been developed for controlling the flow above a three-dimensional turret. The top of the turret is hemispherical, houses a flat optical aperture, and can rotate about two axes (pitch and yaw). The extent of separation and concomitant turbulence levels in the flow above the aperture change as the turret rotates. The control objective is to minimize the separation and turbulence in the dynamic environment created by the articulating turret. The closed-loop control systems include dynamical and measurement-based estimators, controllers, filters, and compensators. These components are developed using both computational data from computational fluid dynamics simulations and experimental data from wind-tunnel runs within the common framework of SMARTFLOW: engineering software for flow control system design. The control systems are evaluated through a series of controlin- the-loop computational fluid dynamics simulations, demonstrating the merits of feedback control through robustness in the presence of measurement noise, modeling errors, and highly unsteady conditions. The computational fluid dynamics simulations also demonstrate reductions in actuation energy below levels required by open-loop systems.