Wingtip Vortex Control Via Tip-Mounted Half-Delta Wings of Different Geometric Configurations

The control of the tip vortex, generated by a rectangular NACA 0012 wing, via tip-mounted half-delta wings (HDWs), of different slendernesses Lambda, root chords c(r), and deflections delta, was investigated experimentally at Re = 2.45 x 10(5). The results show that regardless of Lambda, c(r), and delta, the addition of HDWs consistently led to a diffused tip vortex. The degree of diffusion was, however, found to increase with decreasing Lambda and c(r). HDWs with c(r) <= 50% of the baseline-wing chord c caused a rapid diffusion of vorticity and rendered a weak circulation flowlike tip vortex, suggesting an enhanced wake-vortex decay and alleviation. The c(r) = 0.5c HDW also produced an improved lift-to-drag ratio. A unique double-vortex pattern also exhibited downstream of the c(r) <= 50%c HDW wings. The interaction and merging of the double vortex were expedited by upward HDW deflection.