PIV Investigation of Reynolds Number 200 Photodriven Flapping Wings in Air

Document Type

Conference Paper

Publication Date


Publication Source

48th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition


The flowfield surrounding wings with a pure flapping motion was studied in quiescent air at a Reynolds number of approximately 200 using particle image velocimetry (PIV) in unusually thin illuminated planes (~0.3 mm). Typical wing semi-spans were on the order of a few millimeters. The polymer cantilever wings consisting of monodomain liquid crystal polymers made from azobenzene (azo-LCN) were flapped at 30 Hz at a large amplitude (>170°). Chordwise and spanwise planar slices of the flow across the wings were used to estimate the unsteady aerodynamic forces generated by the flapping wings. This study focuses on the flapping of small-scale wings in order to establish the flowfield topology. Flow in the spanwise direction was significant. Surprisingly little large-scale vorticity was identified. The chordwise results were inconclusive due limitations in the experimental setup. Order of magnitude estimates were made of the aerodynamic contributions to lift which correlated well with empirical estimates.




Permission documentation is on file.


American Institute of Aeronautics and Astronautics

Place of Publication

Orlando, FL