摘要:
某型机采用上单翼低平尾布局,在着陆襟翼小迎角状态时平尾下翼面翼根部位出现局部气流分离,导致飞机振动,力矩特性出现异常变化。本文提出的解决方案是在平尾翼根前方0.12倍根弦长,下方0.30倍根弦长位置的机身上加装一对小展弦比负弯度小翼作为涡流发生器/导流片,一方面加速了后方分离区边界层与外流的能量交换,另一方面利用其上洗作用降低了平尾翼根区域的局部负迎角绝对值。通过数值计算和风洞实验研究表明,优化后的导流片使平尾分离区面积缩小50%,小迎角俯仰力矩拐点推迟4°以上,以较小的性能和结构重量代价解决了局部气流分离问题,拓展了飞机飞行边界。
Abstract:
The aircraft featuring high wing and low horizontal tail encountered local flow sepa-ration at the lower surface of the horizontal tail near the root,which manifests itself as aircraft vibration and abnormal pitching moment.The proposed solution is to install a pair of winglets of small aspect ratio and reversed camber at 0.12 root chord ahead of and 0.30 root chord below the horizontal tail.The winglets function as vortex generator/guiding vane,which enhance the ener-gy exchange between the boundary layer and the outer flow in the separation zone,and also re-duce the local absolute angle of attack of the root section of horizontal tail by the induced up-wash.The numerical simulation and wind tunnel tests reveal that the optimized vortex generator can reduce the separation area by 50%,and delay the starting angle of pitching moment crank by more than 4°.Therefore,the problem of local separation is solved by relatively minor cost of per-formance and weight,and the boundary of flight is enlarged.
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