Effect of piezoelectric actuation on a NACA 0015 aerofoil at subsonic speeds

An experimental study has been conducted to analyse the effects and applicability of piezoelectric actuation at two different chordwise positions on a NACA 0015 aerofoi. The actuators were placed at 25% and 50% of the chord length. The lift and drag forces were measured with actuators operating at 300, 500 and 900Hz and compared with the results obtained with no actuation. The effects of Reynolds number were examined. The boundary layer profiles were investigated using Hot-Wire-Anemometry. The optimum position and frequency to obtain the maximum increase in lift to drag ratio was found to be at 900Hz with actuators placed at 25% of the chord length. The overall maximum increase in the lift to drag ratio was 47%. The stalling angle of the aerofoil was unaffected by actuation.