Active Trailing-Edge Flap Control of Oscillating-Wing Tip Vortex

The tip vortex generated by an oscillating NACA 0015 wing with a moveable trailing-edge flap was investigated at Re = 1.65 x 10 5 by using a miniature triple hot-wire probe. Both positive and negative flap deflections, actuated at different start times, were tested. The negative flap motion was found to be most effective in displacing the vortex position with earlier actuations leading to larger vertical vortex displacements. Negative flap deflections strengthened the vortex, moved the centroid further outboard, decreased the peak vorticity ζ peak , and increased the vortex size. The positive trailing-edge flap motion, however, resulted in a more concentrated tip vortex of reduced vortex strength Γ 0 located further inboard. The lift-induced drag was decreased (increased) for positive (negative) trailing-edge flap, compared to a baseline wing.

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