COMPUTATIONAL STUDY OF CORRUGATED WING IN UNSTEADY MOTION (MAV APPLICATION

Abstract

Leading edge vortex (LEV) formation is considered a dominant factor for high lift production during insect flapping. Previous studies suggest that LEV occupies the separation zone on suction side of the wing and does not shed even after many chords of travel. The development of micro aerial vehicle (MAV) inspired from nature is an active area of research. MAV operates at Reynolds number 104-105; slightly higher than the insects Re range. The motivation behind present research is to investigate whether “stall-absent” phenomenon manifests at Re 34000, representative of MAV. Corrugated dragonfly airfoil with rectangular wing planform is used and wing motion kinematics is restricted to azimuth rotation. Three dimensional finite volume method Fluent is used to numerically solve time dependent incompressible Navier-Stokes equations using pressure based solver. Computed results at Re 34000 and 100,000, reveal the same phenomena of leading edge vortex formation, as observed in case of insects. There is an intense spanwise flow, comparable to chordwise velocity that ensures that the LEV does not grow in size and sheds. Furthermore, parametric study is also conducted to see the effect of angle of attack, acceleration duration, aspect ratio, and wing planform on corrugated wing in sweeping motion. It was also observed that there is no noticeable difference in aerodynamic efficiency of the wing, subjected to geometric variation.