Influence of Wing-tip Dihedral and Planform on Induced Drag

The wing planform as well as the wing frontal shape are numerically investigated with regard to the lift-induced drag reduction. Euler computations have been performed and then post-processed with a far field analysis method for accurate drag predictions. Concerning non-planar wings, this paper provides an unusual way to examine their effects on lift-induced drag by comparing them at the same “deployed” span. Here, deployed span is to be understood as the total curved length of a non-planar wing viewed in its front plane. Far field analysis results show that non-planar wings experience some greater drag at a given lift than planar wings of the same deployed span, even after an optimization process with respect to the lift distribution. Concerning the wing planform influence and especially the crescent shape, another parametric numerical study is presented. Far field results state that moderate drag savings could be obtained with these aft swept wing-tips.