Investigation of Stall Flutter Based on Peters-ONERA Aerodynamic Model

基于Peters-ONERA模型的失速颤振特性研究

School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072, China

Received: 9 September 2017

Abstract

The Peters model is used to simulate the linear aerodynamic force and ONERA stall model is used to simulate the nonlinear aerodynamic force. The state-space equation of the aeroelastic system is established by coupling the structural equation. In order to solve problems, Euler predictor corrector method is used in the time domain and eigenvalue analysis method is used in the frequency domain. The case of dynamic stall is simulated based on Peters-ONERA model and the results imply that the validity of the aerodynamic model. The effect of under relaxation iteration on the stability of static aeroelastic solution is studied. It is found that under relaxation iteration can improve the static aeroelastic solution stability. Then based on frequency and time domain methods, flutter critical characteristic and bifurcation phenomenon are studied. It is found that:(1) Under large angle of attack, the coupling between nonlinear aerodynamic modal and structure modal could induce the instability of the structure modal and single degree of freedom flutter. (2) Under different angles of attack, bifurcation characteristic of aeroelastic system is far different. (3) The sensitivity to the disturbance of the system is different in different ranges. When the disturbance increases, the aeroelastic system will change from stable state to limit cycle oscillation.

摘要

采用Peters模型模拟线性气动力，ONERA失速模型模拟由于动态失速引起的非线性气动力，通过耦合结构运动方程，建立了状态空间（state-space）形式的气动弹性控制方程。采用欧拉预估-校正方法对该方程进行时域推进求解，采用特征根轨迹分析技术在频域内对气动弹性系统进行稳定性分析。基于Peters-ONERA气动力模型对动态失速现象进行模拟，结果表明该气动力模型可以准确地捕捉动态失速气动力的主要特征。采用该气动弹性模型对亚松弛迭代（under relaxation iteration）方法在静气动弹性求解稳定性中的影响进行了研究，研究结果表明，亚松弛迭代可以增强静气弹求解的稳定性。分别采用频域和时域方法对失速颤振中的颤振临界特性和分岔（bifurcation）现象进行了研究，并分析了初始扰动对系统响应的影响。研究发现：①在大攻角下，非线性气动力模态与结构模态的耦合可能导致结构模态的失稳，从而诱发系统的单自由度颤振；②初始攻角的改变会显著影响系统的分岔特性；③在不同的扰动范围内，气动弹性系统对扰动的敏感度不同，扰动增强可能会使系统原先稳定的状态被激发为极限环振荡（limit cycle oscillation，LCO）状态。