抄録
We recorded the flight path of a swift using a video camera with a three axis digital gyro module and investigated the relationship between the swift tail motion and the change in the flight path. The swift was found to open the tail before a steep climb. In order to analyze this relationship, the flow around a swift was numerically simulated.The simulations showed that the open tail stabilized the wake flow for the attack angle of 10°. In addition, the simulation revealed that the transient tilting motion of the tail induced effectively a temporal increase in lift force before flow separation on the tail.
