Abstract
In result years, Micro-Air-Vehicles (MAVs) mimic the flight mechanisms of insects have been attracting significant attention. However, these robots were not practical. One of the reasons for this is that the flying mechanism of insects has not yet been clarified sufficiently. The purpose of the present study is to clarify the dynamic behavior and the detailed structure of the vortices of the flapping butterfly wing. The vortex ring is formed over the wings regardless of the butterflies, but its scale varies among butterflies. When the wings flap upward to top dead position, the vortex ring passes through the butterfly wings completely and grows up to the wake.
