Measurement of Velocity Field around a Flapping Dragonfly by the PIV System

This paper concerned with the flight mechanism of flying insects. Velocity fields around a flapping dragonfly, Crocothemis servilia mariannae were measured by use of a Particle Image Velocimetry (PIV) system. Experimental apparatus is composed of the small wind tunnel, PIV system, and the tethered dragonfly. The flow characteristics around the flapping dragonfly in a uniform smooth wind stream were investigated. The velocity distributions at each stage of the dragonfly flapping were obtained. These velocity distributions clarified the relationship between the flow around the dragonfly and the phase stage difference of the wing flapping stroke. Various experimental data show the generation of the aerodynamic lift at the dragonfly flapping.