On the effect of active flow control on the meandering of a wing-tip vortex

The development of a wing-tip vortex of a rectangular, square-tipped wing having a NACA 0012 airfoil at a chord Reynolds number Re-cw = 2 x 10(5), under the effect of synthetic jet actuation, was experimentally studied. Five control configurations were considered: case C1 with momentum coefficient C-mu = 0.001 and actuation frequency F+ = 0.075; case C2 with C-mu = 0.001 and F+ = 0.15; case C3 with C-mu = 0.001 and F+ = 0.3; case C4 with C-mu = 0.001 and F+ = 0.6; and case C5 with C-mu = 0.001 and F+ = 1.2. Under the most effective configuration, case C3, the vortex was stretched and appeared to be diffuse with a nearly 40% decrease in the peak circumferential velocity and 50% decrease in the core axial vorticity. The vortex core radius largely broadened suggesting that the lower-frequency control configuration allowed the synthetic jet to travel larger distances into the vortex bringing turbulent structures within its core resulting in increased mixing and subsequently a more diffuse vortex.