Effect of an Oscillating Fence Actuator on a Stationary and Pitch Oscillating Wing

Experiments have been conducted to characterize the ability of a fence actuator to alter the aerodynamic loading of stationary and pitch oscillating wings. In particular, an oscillating fence on a NACA-23012 airfoil has been examined using Particle Image Velocimetry (PIV) and time-resolved pressure measurements. The experiments were designed to study the efiect of actuator frequency and the efiect of angle of attack on the surface pressure footprints and the ∞ow fleld behind the actuator. Experiments over a stationary airfoil show that the fence frequency strongly efiects the evolution of the structures generated by the fence. On both stationary and oscillating airfoils, higher actuation frequencies are more efiective in producing higher suction peaks. For an oscillating airfoil, mean angle of attack variation strongly efiects the baseline pressure distribution. The disturbances, however, remain largely unafiected by the variations in mean angle of attack, showing the limited efiect of airfoil oscillation on the disturbances produced by the fence in the range studied. Integrated lift and moment are used to quantify the efiectiveness of the fence actuator. The su‐ciently large changes produced in the lift and moment coe‐cients show the potential of this device for altering aerodynamic loading of the wing and suppressing ∞utter.