Wing-tip vortex control with synthetic jet technology

An experimental investigation on the effectiveness of synthetic jet actuation in affecting and accelerating wingtip vortices dissipation of an unswept, low aspect ratio, rectangular wing at a Reynolds number Rec = 8.04 × 10^4 has been carried out and reported herein. Active control parameters, Cμ and F + have been chosen in order to stimulate vortex instability at its own frequency. The actuation is implemented through synhtetic jets generated passing a sinusoidal signal whose frequency has been set to Crow instability frequency to the loudspeaker. Measurements at z/b = 5, i.e. z/c = 10 considering that A = 2 for the wing model, where the wake has assumed an oscillatory behaviour, have been carried out to verify the control effectiveness. StereoPIV measurements showed that synthetic jets actuation affects vortex evolution, causing a decrease of the axial velocity deficit and of the tangential velocities and of the region characterised by high values of streamwise vorticity.