Flow Visualization Experiments on Tethered Flying Green Lacewings Chrysopa Dasyptera

Abstract

Experiments on dust visualization of the flow around tethered flying green lacewings showed that, contrary to expectations based on the Weis-Fogh clap-andfling mechanism, a leading edge separation bubble does not exist near either fore-or hindwings. At the beginning of the stroke cycle each wing operates as an independent generator of vorticity. The vortex bubbles of all the four wings then unite, producing a single U-shaped bubble. A hypothetical spatial structure for the vortex wake is derived from a series of registrated sections of the wake illuminated with a flat light beam. Some problems of wing functional morphology and insect flight aerodynamics are also discussed.