包含平均旋流的圆环管道声传播的模态分析

Normal mode analysis for the sound propagation in a lined annular duct with mean swirling flow

School of Jet Propulsion, Beijing University of Aeronautics and Astronautics, Beijing 100191, China

摘要: 通过对三维线化欧拉方程的特征模态分析,研究包含平均旋流情况下声波在敷设声衬的圆环管道中的传播.特征模态分析采用谱配置方法计算轴向波数谱及扰动量的分布.当有平均旋流存在时,特征模态谱主要包括近/纯声模态和近/纯对流模态,旋流的存在甚至会改变传播模态个数,从而改变声波传播截止特性.在验证程序正确性的基础上,研究流动参数及声衬对声模态及对流模态的影响.
- 模态分析 /
- 声传播 /
- 旋流 /
- 声衬 /
- 谱配置方法
Abstract: Sound propagation in a lined annular duct with mean swirling flow was investigated via the normal mode analysis of three-dimensional(3-D) Linearized Euler equations,and was calculated as a generalized eigenvalue problem by a spectral collocation technique.Axial eigenmodes spectrum which are mainly composed of nearly/purely acoustic modes and nearly/purely convected modes with mean swirl and relative unsteady disturbances can then be determined.Mean swirl may even change the number of the propagating acoustic modes,and consequently affect the cut-on/cut-off characteristics of sound propagation.After validation of the approach,the effects of flow parameters and liner on the acoustic modes and convected modes are discussed.
- normal mode analysis /
- sound propagation /
- swirling flow /
- liner /
- spectral collocation technique

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