摘要
采用多项式迟滞非线性模型建立二元机翼气动弹性运动方程,并用数值积分法进行求解。通过系统响应振幅随来流速度变化的分叉图和频谱分析发现,俯仰方向由于含有非线性因素,振动中的高阶分量随速度提高不断增加,并引起高次分叉。重点研究“机翼/空气”质量比以及“沉浮/俯仰”两个自由度的自然振动频率比对非线性颤振速度边界的影响,并提出可以通过提高自然振动频率比来减小迟滞非线性因素的不利影响。
The dynamical equation of a two-dimensional airfoil with polynomial hysteresis nonlinearity in pitch is solved using Runge-Kutta time marching integration. Firstly, the bifurcation diagrams and power spectral densities of pitch and plunge motion are obtained;and it is found that as the existence of nonlinearity there are a number of frequency peaks in the spectrum, which lead to the bifurcation of the pitch amplitude. Then, the effects of airfoil/air mass ratio and plunge/pitch natural frequency ratio on flutter boundary are studied. The resuits show that in order to increase the nonlinear flutter speed,larger plunge/pitch natural frequency ratio can be used.
出处
《航空学报》
EI
CAS
CSCD
北大核心
2007年第3期600-604,共5页
Acta Aeronautica et Astronautica Sinica
基金
国家自然科学基金(10272012)
教育部新世纪优秀人才基金(NCET-04-0169)
关键词
非线性气动弹性
极限环振荡
龙格-库塔数值积分
迟滞非线性
分叉
颤振速度
nonlinear aeroelasticity
limit circle oscillation
Runge-Kutta numerical integration
hysteresis non linearity
bifurcation
flutter speed
