平板耦合颤振过程中气动能量转换特性

Aerodynamic energy transfer characteristics in coupled flutter of plate

基于分步分析思路对耦合颤振运动方程进行解耦,通过引入考虑阻尼影响的初始运动方程,建立了结构-气流系统颤振能量机理的分析框架。结合平板风洞试验研究了颤振发生过程中系统内主要气动能量的变化规律。研究结果表明在平板耦合颤振过程中联合气动导数数A1*H3*建立了能量在两个自由度上传递的途径,并且在颤振发生过程中由于扭转振动和竖向振动的相位差逐渐减小,使得该联合气动导数对系统的输能能力不断增强。扭转气动阻尼是系统的主要耗能项,并且耗能能力与导数A2*的数值密切相关而与相位差没有关系。扭转气动刚度在一个振动周期内对系统能量几乎没有贡献,对耦合颤振的影响很小。

Coupled motion equations of flutter were uncoupled by step-by-step analysis method. The energy mechanism of structure-fluid flutter was analysed, considering the damping effects in motion equations. The main aerodynamic energy characteristics of plate were studied by wind tunnel tests. The results show that the coupling aerodynamic derivative A1*H3* builds an energy transmission way through a system of two degrees of freedom. The phase difference between torsional vibration and vertical vibration is gradually decreased in the process of flutter, which strengthens gradually the energy transmission by coupling aerodynamic derivatives. The energy of system is mainly dissipated by the aerodynamic damping due to twist motion. The energy dissipation capacity is closely related with aerodynamic derivative A2*, but has no relationship with the phase difference. The aerodynamic stiffness of twist motion has no contribution to the system energy in a vibration cycle, so it has very small inference on the coupled flutter.