プラズマアクチュエータを用いた一様流中におかれた振動平板まわりの流れの制御

抄録

Development of micro air vehicles (MAV) has been progressed along with understanding of the flight mechanism of insects. In insect flight, it is well known to control the vortex shedding from flapping wings with feathering motions is important. In order to control flow around flapping wings with simplified sinusoidal motion, plasma actuators (PA) were introduced instead of complicated feathering motion control. In this study, flow field around an oscillating flat plate in a uniform flow were measured with a wind tunnel. Numerical simulations were also performed to investigate effects of PA control on lift of the oscillating plate. Since the leading edge flow separation and vortex shedding from the trailing edge were suppressed in the case of continuous control, the lift was improved in the up-stroke period. However, the leading edge flow separation which contribute to lift generation was reduced in the down-stroke period. As a result, the lift improvement was 0.7%. Also, when the control was conducted only during up-stroke, the lift could be effectively increased by 8.8%. In the down-stroke period, the separation vortices around the leading edge make negative pressure on the upper surface, so the lift force was generated. During the up-stroke, the vortex shedding from the trailing edge of the lower surface was suppressed by the control. As a result, the lift was recovered in the up-stroke period. It reveals that the control timing plays an important role in flow control of the oscillating wing.