Abstract
The three-dimensional flows in the Weis-Fogh mechanism are studied by flow, and numerical simulation by the vortex method. The vortex method -- especially the vortex stick method, is employed to investigate the vortex structure in the wake of the two wings. The pressure is estimated by the Bemoulli equation, and the lift on the wing is also obtained. It was found that the eddies near the leading edge of each wing, in the fling stage take, take a convex shape. This was because the eddies shed from both tips entrain the flows, and the downwash in the rotating stage is deflected toward the outside. The outside tip vortex is stronger than the inside vortex. The lift coefficient on the wings in this mechanism is almost independent of the Reynolds number.
