小型反馈射流振动器的动态特性研究
Research on Dynamic Characteristics of a Small-scale Feedback Fluidic Oscillator

针对小型反馈射流振动器在低雷诺数下的流场的动态特性，利用粒子图形测速法（PIV）对其进行了二维测量实验，得到了不同流量下内部流场在振动稳定状态时的速度分布，流量范围为100~300 ml/min。通过实验监测上下反馈通道出口处的Y方向分速度并分析射流的振动过程和原理。数据分析方法包括快速傅里叶变换和小波变换，得到不同流量时的振动频率，进而得出振动频率特性和斯特罗哈数特性。结果表明：该小型反馈射流振动器内部流场呈周期振动，快速傅里叶变换和小波变换得到的振动频率接近，频率特性和斯特罗哈数特性均为非线性。
Particle image velocimetry(PIV) was conducted in order to get the dynamic characteristics of the two dimensional fluid fields in a small-scale feedback fluidic oscillator operated under low Reynolds number flow. Velocity distributions of the whole internal fluid flow under steady state were gained when the flow rate ranged from 100 to 300 ml/min. The jet flow was analyzed by monitoring the Y components of velocities in the outlets of two feedback channels in the experiments. Oscillation frequencies under different flow rate were obtained by two data analysis methods, fast Fourier transforms and wavelet transforms. Characteristics of oscillation frequency and Strouhal number were also obtained. The results verified that the internal fluid flow of the small-scale feedback fluidic oscillator presented periodic oscillation, the oscillation frequencies obtained by fast Fourier transforms and wavelet transforms were nearly approximate, the characteristics of oscillation frequency and Strouhal number were nonlinear