Experimental and computational aerodynamic investigation of avian-based rigid flapping wings for MAV applications Conference Paper uri icon


  • Copyright 2014 by the authors except where noted. All rights reserved. Targeted experiments in parallel with a systematic CFD analysis were performed for a MAV-scalerigid flapping-wing in forward flight. Two-component time-resolved particle image velocimetry (PIV measurements were performed in an open circuit wind tunnel on a wing undergoing pure flap win; kinematics at a fixed wing-pitch angle. Chordwise velocity fields were obtained at equally spaced span wise sections along the wing (30% to 90% span) at two instants during the flap cycle (mid-downstroke and mid-upstroke) for the reference Reynolds numbers of 15,000. The flowfield measurements wen used for the validation of the 3-D CFD model. The CFD analysis used a compressible Reynolds Averaged Navier Stokes (RANS) solver to resolve the complex, highly vortical, three-dimensional flow The objectives of the combined efforts were to understand the unsteady aerodynamic mechanisms and their relation to force production on a rigid wing undergoing an avian-type flapping motion. Overall the CFD results showed good agreement with the experimental data for resolution of the overall high]; unsteady and vortical flow field. A vorticity summation approach used to calculate the strength of this leading edge vortex (LEV) from the PIV measurements and also from the CFD generated flow field showed comparable results. A hybrid momentum-based method was used to estimate the section a vertical force coefficient from the PIV measured flow field, which agreed well with the CFD force pre diction over a range of flapping frequencies and wing pitch angles. In general, it was observed that the flow over the wing was highly susceptible to changes in induced angle of attack resulting from the flap ping motion and variations in reduced frequency, which manifested in the predicted airloads. Basel on the computational analysis, the spanwise flow component was not significant except near the wing tip and therefore, most of the vertical force and propulsive thrust produced could be explained using the magnitude and direction of the sectional lift and drag forces acting on the wing. For the present wing kinematics most of the upward vertical force was produced during the downstroke and positive propulsive thrust during the upstroke, which shows the need for appropriate temporal and spanwise pitch modulation of the wing along with flapping to produce positive vertical force and propulsive thrust during the entire flap cycle.

published proceedings

  • American Helicopter Society International - 5th Decennial AHS Aeromechanics Specialists' Conference 2014: Current Challenges and Future Directions in Rotorcraft Aeromechanics

author list (cited authors)

  • Mayo, D. B., Lankford, J. L., Benedict, M., & Chopra, I.

complete list of authors

  • Mayo, DB||Lankford, JL||Benedict, M||Chopra, I

publication date

  • January 2014