The experimental research will focus on evolution and control of aerodynamic forces on lifting surfaces during dynamic maneuvers. The forces and moments will be varied independently by dynamically tailoring the surface pressure distribution on lifting surfaces using a sparse array of hybrid fluidic actuators to manage the generation, accumulation (trapping), and regulation of spanwise vorticity near the lifting surface and of streamwise vorticity near the wing tips (especially on low aspect ratio planforms). Actuation strategies will include transitory effects near the leading edge and wingtips to regulate transient accumulation and shedding of vorticity and the manipulation of the Kutta condition near the trailing edge. A salient feature of this research is that dynamics of the lifting surface motion and the fluid dynamics (flow) are intimately coupled during dynamic maneuvers. Hence, the dynamics of the flow under control will be strongly affected by the rigid-body dynamics. Changing the stability of the vehicle to enhance maneuverability can strongly amplify this coupling, requiring that the experimental research be strongly coupled with the controls research (Closed-Loop Adaptive Flight/Flow Control).

The research will use 1 m scale wind tunnel model based on UAV airfoil. The model will be constructed from light-weight composite material, instrumented with arrays of hybrid synthetic jet actuators, pressure sensors (ultimately MEMS-based pressure sensors), and microtufts (Sensors and Actuators). The experiments will be conducted in parallel in two wind tunnels focusing separately on 2-D and 3-D (wing tip) flow control approaches with emphasis on rapid generation of transitory increments in aerodynamic forces and moments by incremental changes in 2- and 3-D vorticity distributions. The precise form of the actuation and its location are part of the research effort. The research will proceed systematically in concert with both the development of advanced sensor arrays and the development of detailed information about flow structure from both computational and experimental components of the MURI program.

The 2-D and (ultimately) 3-D models will be mounted to a programmable, 2-DOF (pitch and plunge) traverse electromechanically driven by a dedicated feedback controller that will remove the parasitic mass and rotational inertia of the dynamic support system and of the model. This will enable investigations of the behavior and control of a range of virtual air vehicles, all having the same wing as the wind tunnel model, but with static margins that can be adjusted by the traverse controller, including unstable configurations for high maneuverability. Within the constraints of the test section, the virtual vehicle will execute commanded maneuvers driven by its flow control actuators. An integrated, adaptive controller operating with feedback from both the vehicle and the flow will command the actuators. Model position, speed, and acceleration will be monitored using optical encoders, and the aerodynamic forces (lift and drag) and moment (pitch) will be inferred from force transducers between the model and the support system.