民机极限飞行状态的动态气动力试验与建模

飞行失控是造成民机灾难性航空事故的重要因素，飞行失控中飞机难以避免超出正常飞行包线范围，进入具有复杂非线性和非定常动态气动特性的极限飞行状态。本文开展典型民机布局飞机极限飞行状态的动导数、大振幅试验，对大迎角动态气动力的参数影响规律以及非线性、非定常特性进行分析和建模。结果表明，在飞机失速到过失速区域，飞行姿态快速变化过程中动态气动力的非线性和非定常特征显著；在动导数试验和建模中，考虑运动角速率的影响，可以预示气动力非线性的迎角范围，并捕捉到关于飞机动稳定性演化的关键特征；利用Goman-Khrabrov状态空间模型结合大振幅试验，可以确定模型中表征非定常特征的关键时间常数，获得特定极限飞行状态运动中的非定常动态气动力特性。研究方法和结果为开展民机极限飞行状态的动态气动力风洞试验设计与建模提供了一个可行途径，能改进飞机飞行失控预防、极限状态改出、飞行模拟训练和飞行事故分析等。

Unsteady aerodynamics test and modeling of civil aircraft under extreme flight conditions

Loss of control is an important cause of catastrophic aviation accidents, possibly exposing the aircraft under extreme flight conditions with complex nonlinear and unsteady aerodynamic characteristics beyond the normal flight envelope. The dynamic derivative and large amplitude wind tunnel tests under the extreme flight conditions are conducted to analyze the impact factors for dynamic aerodynamics and the nonlinear and unsteady characteristics. Results show that the nonlinear and unsteady characteristics of dynamic aerodynamics are significant in stall to incipient spin regions; for dynamic derivative test and modeling, the impact of the angular velocity of motion can be considered to predict the range of angle of attack of aerodynamic nonlinearity and capture the key characteristics related to the dynamic stability of flight maneuvers; using the Goman-Khrabrov state space model combined with the large amplitude test, the key time constants of the unsteady characteristics in the model can be determined, and the unsteady aerodynamic characteristics in the specific extreme flight state motion can be obtained. The research methods and results provide a promising way for the design and modeling of the dynamic aerodynamic test of civil aircraft under extreme flight conditions.