航空学报 > 2022, Vol. 43 Issue (8): 125582-125582   doi: 10.7527/S1000-6893.2021.25582

民机极限飞行状态非定常气动力建模

岑飞1, 刘志涛1, 蒋永1, 郭天豪1, 张磊1, 孔轶男2   

  1. 1. 中国空气动力研究与发展中心 低速空气动力研究所, 绵阳 621000;
    2. 中国空气动力研究与发展中心 计算空气动力研究所, 绵阳 621000
  • 收稿日期:2021-03-29 修回日期:2021-06-02 出版日期:2022-08-15 发布日期:2021-06-01
  • 通讯作者: 刘志涛,E-mail:lztustc2008@163.com E-mail:lztustc2008@163.com

Unsteady aerodynamics modeling of civil transport configuration under extreme flight conditions

CEN Fei1, LIU Zhitao1, JIANG Yong1, GUO Tianhao1, ZHANG Lei1, KONG Yinan2   

  1. 1. Low Speed Aerodynamics Institute, China Aerodynamics Research and Development Center, Mianyang 621000, China;
    2. Computational Aerodynamics Institute, China Aerodynamics Research and Development Center, Mianyang 621000, China
  • Received:2021-03-29 Revised:2021-06-02 Online:2022-08-15 Published:2021-06-01

摘要: 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。选择具有布局典型性的CRM民机标模,开展极限飞行状态大振幅振荡测力试验,获得极限飞行状态非定常气动力数据;基于大迎角流动分离物理机理和Goman状态空间建模方法,提出了针对大型民机极限飞行状态的非定常气动力模型并验证了模型的泛化能力;将非定常气动力模型与飞机运动方程结合,形成非定常气动力/非线性运动状态方程组,进行气动/运动耦合分岔分析,预测了极限飞行状态飞机非线性运动,最后利用风洞模型飞行试验进行极限飞行状态动力学特性验证。结果表明,在民机非定常气动力建模中,改进状态空间模型结构,针对机翼和平尾,分别引入反映其空间流场特征的状态变量,改进后的模型实现了民机纵向非定常气动力建模,尤其是解决了俯仰力矩非定常建模问题,模型具有良好的泛化能力;结合非定常气动力模型和飞机运动方程进行的极限飞行状态非线性运动分岔分析,可以准确预测极限环振荡等非线性运动;通过风洞模型飞行试验,准确复现和验证了极限飞行状态飞行动力学特性的发展演化,实现了非定常气动力建模和非线性飞行动力学分析结果的试验验证。研究方法和结果为民机极限飞行状态的气动与运动特性的建模分析提供了一个可行途径,从而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。

关键词: 民机, 极限飞行状态, Goman-Khrabrov模型, 分岔分析, 飞行试验

Abstract: Loss of control is an important factor causing catastrophic aviation accidents, and may lead to extreme flight conditions with complex nonlinear and unsteady aerodynamic characteristics beyond the normal flight envelope. The CRM civil aircraft is selected in this study to conduct a large amplitude oscillation force measurement experiment under extreme flight conditions, and the unsteady aerodynamic data of the aircraft are obtained. Based on the physical mechanism of flow separation at a high angle of attack and the method of Goman state-space model, the structure of the unsteady aerodynamic model for large civil aircraft under extreme flight conditions is proposed, and the predicted ability of the model is verified. The unsteady aerodynamic model is combined with the aircraft motion equations to form the flow/motion state equations. Analysis of the aerodynamic/motion coupling bifurcation is then conducted to predict the evolution characteristics of the aircraft flight motion under the extreme flight condition. The dynamic characteristics are verified by the wind tunnel model flight experiment. The results show that the structure of the unsteady aerodynamic model can be improved by dividing the state variables reflecting the flow field characteristics of the wing and the horizontal tail, respectively. The improved model can accurately capture the longitudinal unsteady aerodynamic characteristics of civil aircraft, and particularly solve the problem of unsteady modeling of the pitch moment. The bifurcation analysis of nonlinear motions such as the limit cycle oscillation under extreme flight conditions can be accurately predicted; the development and evolution of flight dynamics characteristics under the extreme flight condition can be accurately reproduced and verified through the wind tunnel model flight experiment, thereby providing controlled and repeatable experimental conditions for unsteady aerodynamic modeling and verification of nonlinear flight dynamics analysis results. The research methods and results provide a feasible approach to the study of aerodynamic and kinematic characteristics of civil aircraft under extreme flight conditions, so as to improve the prevention and recovery from loss of control, pilot training with flight simulation and flight accident analysis.

Key words: civil aircraft, extreme flight conditions, Goman-Khrabrov model, bifurcation analysis, flight test

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