0626 Vortex ring developed over a butterfly wing and in wake field and its dynamic lift

The flow field around the butterfly wing becomes a complicated vortex flow structure. This is because the elastic deformations of the wings and changes in the flow field have significant bi-directional impacts, and the fluid structure interactions are strong. Moreover, the vortex flow and its dynamic behavior generated by the flapping wings of the butterfly are expected to be important for generating the aerodynamic forces required for flight. In the present study, we attempt to clarify the relationship between the vortex ring over the wing and the dynamic lift generated by the flapping wing. We measured the dynamic forces of the flapping butterflies. Moreover, we predicted the dynamic lift generated by the butterfly wing using the circulation of the vortex ring and compared predicted lift with that measured directly.