PIV計測による翼端渦の発達過程に対する翼端振動の影響評価

抄録

The suppression of wing-tip vortex is desirable to reduce the induced drag of airplane. In the present study, the decay of the wing-tip vortex is enhanced by introducing wing-tip vibration. A vibrating wing-tip was attached to a NACA0012 half wing model. The tangential velocity of the vortex was measured at x/c = 4 by 2D2C PIV. The vibration frequency and the angle of attack of the wing are selected as parameters. The vortex strength is evaluated by the circulation calculated by line-integral of the tangential velocity of the vortex. When the tip vibration is introduced, the circulation significantly drops at a certain frequency. This critical frequency increases with the angle of attack. It is found that the maximum tip velocity at the critical frequency corresponds to approximately 30 % of the maximum tangential velocity of the vortex for all the angle of attacks tested. The vortex completely decays when the ratio exceeds around 65 %.