Gliding performance of 3-D corrugated dragonfly wing with spanwise variation

Computational fluid dynamics (CFD) analyses are conducted to evaluate the gliding performance of a three-dimensional (3-D) corrugated wing while considering variations in the corrugation pattern across the wing span. Comparisons with the smoothly profiled counterpart assess the overall effect of wing corrugation on the gliding performance of the 3-D dragonfly wing, with primary focus on the effect of three-dimensionality as compared to the 2-D model. Earlier simulations of both 2-D and 3-D gliding corrugated wings showed oscillations on lift and drag, while in nature, such force fluctuation would be undesirable and unrealistic. In contrast, no non-realistic fluctuations are present in this simulation. The feature included here, which has been neglected in the earlier studies, namely the variation of leading edge orientation along the wing span, is the crucial detail for preventing such non-realistic oscillations. Furthermore, strong spanwise flow occurs in the 3-D corrugated wing used in this study, which earlier models have been incapable to capture. (C) 2016 Elsevier Ltd. All rights reserved.