Reduction of Induced Drag in Configuration Flight using Wing Twist at Post-Stall Angles of Attack

摘要

In this paper, a novel decambering technique has been implemented using a vortex lattice method to study the effects of wing twist on the induced drag of individual lifting surfaces in configuration flight. The effects of both geometric and aerodynamic twist are studied. 2D C_1 - α and C_m - α from XFoil at Re = 1 × 10~6 for NACA0012 airfoil is used as input to predict 3D post-stall aerodynamic characteristics for a single wing with geometric twist and compared with literature. Aerodynamic twist is implemented by using different airfoils along wing-span and wing C_L - α and C_(di) - α are compared with experiment. The effect of asymmetric aerodynamic twist on the leading wing shows distinct changes in the span-wise distribution of C_l and C_(di) on the trailing wing and throws up interesting inferences about formation flight aerodynamics.