旋翼诱速的横向分布

 直升机前飞时,旋翼平面处诱速的横向分布,究竟前行桨叶半边大还是后行半边大,迄今无定论。本文根据经典涡流理论,全面分析环量Γ_o及Γ_(1s)对诱速横向系数υ_(1s)的贡献,然后利用桨叶挥舞条件,通过Γ_o及Γ_(1s),不同分布的组合情况进行估算,发现存在着一个临界半径位置。在临界半径以外υ_(1s)为负,即前行桨叶的诱速小于后行半边的;在临界半径以内υ_(1s)为正,前行桨叶的诱速大于后行桨叶的。上述结果得到实验证实。

LATERAL INDUCED VELOCITY DISTRIBUTION OF A HELICOPTER ROTOR

For a helicopter in forward flight, it is still unknown whether the lateral induced velocity on the advancing side of the rotor plane is. larger than that on the retreating side or vice versa. In order to clarify the essential feature of the lateral induced velocity distribution of the helicopter ro tor, the contributions of circulations 0 and 1s to the sine component of the induced velocity are analysed in this paper, based on the classical vortex theory. Then, using the flapping condition of the rotor blade, a critical radius position is found. On the outboard blade(outside of the critical radius position), uls- negative, the induced velocity on the advancing side is amaller than that on the retreating side whereas on the inboard blade (inside of the critical radius position), vls is positive, the indeced velocity on the advancing side is larger than that on the retreating side. This conclusion is verified by experiments.