运输飞机非常态俯仰振荡分析

对某运输飞机在大襟翼偏度下的非常态俯仰振荡原因进行了分析。研究结果表明，该运输飞机在大襟翼偏度下飞行时因平尾受机翼的强下洗作用导致平尾下翼面发生局部分离，该分离未达到失速分离，从而引起飞机非常态的俯仰振荡。分离的主要原因是机身与平尾融合处抗流场逆压梯度能力下降，导致在大襟翼偏度飞行时出现局部分离，使得飞机出现纵向非常态俯仰振荡。该结论在风洞试验及该运输飞机试飞中得到验证。

Abnormal Elevation Oscillation Research of Transport Aircraft

The longitudinal aerodynamic characteristics of transport aircraft at the large flap angle are studied by the numerical method, and the flow mechanisms for such flows are analyzed. The results show that the limited separate flow of horizontal tail at the la rge flap angle causes the dis-original elevation oscillation, and the blended area of tail and body has large adverse pressure gradient, where exists the partial separated flow. The flow characteristics in this area causes the abnormal elevation oscillation for the aircraft. The results are also validated by experiments and flight tests.