Aerodynamic performance of a wing with a deflected tip-mounted reverse half-delta wing

The impact of a tip-mounted 65 degrees-sweep reverse half-delta wing (RHDW), set at different deflections, on the aerodynamic performance of a rectangular NACA 0012 wing was investigated experimentally at Re = 2.45 x 10(5). This study is a continuation of the work of Lee and Su (Exp Fluids 52(6):1593-1609, 2012) on the passive control of wing tip vortex by the use of a reverse half-delta wing. The present results show that for RHDW deflection with -5 degrees <= delta <= + 15 degrees, the lift was found to increase nonlinearly with increasing delta compared to the baseline wing. The lift increment was accompanied by an increased total drag. For negative RHDW deflection with delta < -5 degrees, the RHDW-induced lift decrement was, however, accompanied by an improved drag. The deflected RHDW also significantly modified and weakened the tip vortex, leading to a persistently lowered lift-induced drag, regardless of its deflection, compared to the baseline wing. Physical mechanisms responsible for the observed RHDW-induced phenomenon were also discussed.