摘要
高速空腔流动包含复杂波系结构,这些复杂波系的传播和演化导致流动产生自持振荡而引起强噪声,空腔噪声在频谱上包含多个具有离散频率的声模态,深入理解各阶声模态的演化规律可为发展噪声控制方法提供理论基础.通过分析亚声速和超声速情况下空腔两端的波系散射过程并考虑三维展向流动,分别建立了针对亚声速和超声速空腔流动的三维波系模型.三维波系模型包含了空腔中不同波系之间的非线性相互作用,这种非线性作用可导致产生不同于Rossiter模态的其余频率成分.基于三维空腔流动实验测量的压力信号数据,对模型中的参数进行了线性估计,采用快速傅里叶变换、双谱分析和小波变换等方法对压力信号进行了分析,结果表明:振荡主模态之间会产生非线性作用,这种非线性作用产生了幅值较高的谐频,主要的振荡模态之间存在模态切换现象,且模态切换呈低频特征,整体表现出随机性特性.
The high-speed flow passing through an open cavity will generate complex wave structures.The propagation and evolution of these waves can lead to the self-sustained oscillation of the cavity flow and cause strong noise.The cavity noise may contain multiple acoustic modes with discrete frequencies in the spectrum.A clear understanding of the evolution of the oscillation mode will provide a theoretical basis for the study of the noise control method.By analyzing the waves scattering process at both ends of the cavity at subsonic speed and supersonic speed and considering the three-dimensional spanwise flow,the three-dimensional wave model for subsonic cavity flow and supersonic cavity flow are established respectively.The model involves the nonlinear interaction between different waves in the cavity,which may produce other components different from the Ross iter mode.Based on the pressure signal data measured from the experiments on cavity flow for Mach numbers 0.9 and 1.5,the parameters in the model are linearly estimated.The pressure signals are analyzed by using FFT,bispectral analysis,and continuous wavelet transform.The results show that there are nonlinear interactions between the main oscillation modes,thus producing strong harmonics.The mode-switch phenomenon is observed in both the subsonic case and the supersonic case.The mode-switching exhibits lowfrequency behavior and shows randomness as a whole.
作者
罗勇
杨党国
武从海
李虎
张树海
吴军强
Luo Yong;Yang Dang-Guo;Wu Cong-Hai;Li Hu;Zhang Shu-Hai;Wu Jun-Qiang(State Key Laboratory of Aerodynamics,Mianyang 621000,China;High Speed Aerodynamics Research Institute of Chinese Aerodynamics Research and Development Center,Mianyang 621000,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2022年第19期182-191,共10页
Acta Physica Sinica
基金
国家自然科学基金(批准号:12102450,12172374,11732016)
四川省科技计划项目(批准号:2018JZ0076)
国家数值风洞工程(NNW)资助的课题。
关键词
空腔流动
波系
模态演化
气动噪声
时频分析
cavity flow
wave structures
mode behavior
aeroacoustics
time-frequency analysis
