Abstract
In nature, flight organisms change flow field around the wing and produce fluid force according to flapping motion of flight organism wing. Therefore, the flow field around the flight organism wing and fluid force are remarked academically. We clarified a vortex ring generated over a butterfly wing in downward and upward flapping motion using PIV measurement. We estimated the dynamic lift from the circulation of a vortex ring generated over a butterfly wing. After that, we measured the dynamic lift to verify the estimation result. The estimation and measurement result are almost same in downward flapping motion. However, estimation result of dynamic lift doesn't correspond to the measurement result of dynamic lift. The reason is that we just evaluated a vortex ring over the butterfly wing but we didn't evaluate a vortex ring generated wake field of the butterfly. So we estimated the dynamic lift using the vortex ring over a butterfly wing and wake field of the butterfly. Therefore, we clarified that estimation result of dynamic lift correspond to the measurement result of dynamic lift.
