Post-Stall Flow Control of Sharp-Edged Wings Demetri Telionis and Pavlos Vlachos, VA Tech Objectives Use microactuators and flow control to increase lift, manage drag and reduce buffeting of sharp wings at high angles of attack Transitions Such devices could improve the maneuverability of fighters like the F22, or new UAV aircraft. They could also allow supersonic aircraft to take off and land without the need of large wings and/or heavy leading edge flaps.

The oscillating mechanism and laser positioning feedback mechanism.  

Cp x/c Airfoil pressure coefficient distribution at different angles of attack. Suction and pressure sides. No actuation. For Reynolds number, see Table.

as in Table 5.2.1. PK: peak values. PSD f PSD at angles 40 through 25. Pitot 3. Reynolds number and freestream velocity as in Table 5.2.1. PK: peak values.  

leading edge flap actuation;  trailing edge flap actuation. Normal force coefficient variation with excitation frequency. Angle of attack: 20; leading edge flap actuation;  trailing edge flap actuation.

St F   Strouhal number variation with excitation frequency. Angle of attack: 20;  leading edge flap actuation;  trailing edge flap actuation.

Normal force coefficient variation with excitation frequency Normal force coefficient variation with excitation frequency. Angle of attack: 15; leading edge flap actuation.

Strouhal number variation with excitation frequency Strouhal number variation with excitation frequency. Angle of attack: 15; leading edge flap actuation

Normal force coefficient variation with excitation frequency. Angle of attack: 10;leading edge flap actuation.

Cp x/c Pressure coefficient distribution for controlled case. Angle of attack 10. Leading edge excitation.

Exploded View of Flow Control Device

Cross Section of Flow Control Device. Blowing Slot External Cylinder External Cylinder Internal Cylinder Internal Cylinder   Cross Section of Flow Control Device.

Leading Edge Aligned with Pitot Rake

Sharp-edged wing with the leading –edge attachment that houses the rotating cylinder and the accumulator chamber.

Photograph of the inside of the wing, showing the pneumatic flow control system and the pressure tubes. The skin of the model is open in this photograph. It bolts down on the bulkheads to form the shape of a sharp-edged airfoil.

Technical Problems and Future Work • Lock on and feedback control - shedding locks to driving and then jumps - control law must anticipate jump • Locations and direction of control jet - LE or TE? - Angle? And location • Sweep angle effects - Vortex line orientation - Flow control of different flow phenomena