Effect of corrugation on the aerodynamic performance of three-dimensional flapping wings

The effect of corrugation implemented in cambered wings on the aerodynamic performance of three-dimensional flapping-wings was studied. For the first time, the measured wing kinematics of a hover-capable tailless flapping-wing micro air vehicle, which is called KUBeetle, was employed for all wing profiles. The forces and flow structures were obtained using the computational fluid dynamics (CFD) method via the commercial software ANSYS-Fluent. Different corrugation heights of 0 (non-corrugated), 3%, and 6% of local chord length were considered. For each corrugation height, the effect of corrugation near leading and trailing edges were also investigated. For A-group wings in which the corrugation was placed over all of the chord, the lift and drag increased, compared to the non-corrugated profile in downstroke. However, during upstroke when the stroke direction is reversed, the corrugation profiles reversed upside down, causing reduction in lift and drag. Meanwhile, for P-group wings in which 20% chord length near the leading edge and trailing edge were non-corrugated, forces decreased slightly in both the down- and up-strokes. Especially, the characteristics of aerodynamic force generation including lift-to-drag ratio of the P-group wing with a corrugation height of 3% of local chord length was very close to those of the non-corrugated cambered wing. Since wing corrugation is expected to stiffen the membrane wing, this particular wing may replace the current wing removing vein structures, which can contribute to lighter weight and lower power consumption to overcome inertial force at the stroke reversals. (C) 2020 Elsevier Masson SAS. All rights reserved.