Feedback Control of a Flow around a Symmetric Airfoil (Applicability of the Electromagnetic Actuators for the Wind Speed Decrease)

Abstract

Lift and drag of a symmetric airfoil with miniature electromagnetic actuators have been measured in the low Reynolds number region from 3 × 10⁴ to 1× 10⁵. It was found that the coefficient of the maximum lift increased as the Reynolds number was increased. The actuation made the maximum lift larger than that in the no-actuation case for each Reynolds number, although its effectiveness was the largest at the lowest Reynolds number of 3× 10⁴ and became smaller as the Reynolds number was increased. Even in the case of the wind speed decrease, it was demonstrated that the actuation was effective to avoid the stall. Feedback control using increase/decrease of angle of attack was also effective to maintain the high lift in the case of the wind speed decrease and the additional feedback operation of actuators worked well to suppress the abrupt decrease of the lift.