襟翼翼尖涡控制飞机尾流机制实验研究

Experimental Research on Aircraft Wake Flow Control by Flap Wingtip Vortex

为了研究襟翼小涡与主翼尖涡相交不稳定性触发条件,采用矩形机翼模型产生一对翼尖涡,同时在机翼上安装不同宽度及攻角的襟翼,对35个翼展下诱发R-L(Rayleigh-Ludwig)不稳定性的最佳涡系参数组合进行了研究。结果表明:通过水槽流动显示实验发现,单主翼尾涡在第35个翼展处未发生明显变化,能量衰减缓慢;加装襟翼后尾流不稳定性被触发,衰减效果明显,在一定范围内尾涡能量衰减值随着襟翼攻角的增大而增大;环量统计半径Rd=50mm时,对主翼尖涡环量进行PIV(Particle Image Velocimetry)分析时发现,当主翼攻角α=8°,襟翼攻角β=28°,襟翼宽度b=55mm,来流速度V=0.5m/s时尾涡能量消散最快,主翼尖涡环量在第35个翼展时衰减为第一个翼展的28%;证实通过安装合适的襟翼可以有效地控制飞机尾流,加速其破裂和消散。

In order to study the triggering conditions of the intersecting instability of the flap wingtip vortex and the main-wing vortex,the rectangular wing model is used to generate a pair of wingtip vortices with different flap widths and attack angles and the optimal vortex parameters for triggering R-L(Rayleigh-Ludwig)instability are investigated within 35 wingspans.The flow visualization experiments show that the single main-wing vortex has not changed significantly at 35 th wingspan,and the energy attenuation is very slow.The wake flow instability is activated after the flap installation and the main-wing vortex energy dissipates much more quickly with the increase of the flap attack angle in certain extent.The PIV(particle image velocimetry)analysis(statistical radius for the wake flow circulation Rd=50 mm)has found that the wake flow energy dissipates most quickly while the main-wingattackangleα=8°,theflapattackangleβ=28°,theflapwidth b=55 mmandtheflowvelocity V=0.5 m/s,and the main-wing’s 35 th wingspan vortex circulation reduced to the 28%of 1 st wingspan.The aircraft wake flow can be controlled effectively by installing the suitable flaps and the fracture and dissipation of the main-wing vortex can be accelerated.