Volume 37, Number 6, December 2019
|Page(s)||1148 - 1157|
|Published online||11 February 2020|
Effects of Shear Layer Characteristics on Acoustic Propagation and Source Localization
School of Aerospace Engineering, Xiamen University, Xiamen 361102, China
2 Key Laboratory of Aerodynamic Noise Control, China Aerodynamics Research and Development Center, Mianyang 621000, China
The shear layer characteristics of an open-jet acoustic wind tunnel are of key importance on measurements of aeroacoustics. The effects of thickness, spreading angle and strength of shear layer on acoustic propagation and source localization are investigated through the mean/spreading shear layer with a self-similar velocity distribution. Based on the shear flow, the acoustic propagation is computed by the linearized Euler equations via a source term, and then source localization is obtained from beamforming technique combined with the theory of Amiet. Results show that the numerical method can precisely capture the refraction and reflection after sound traversing shear layer. The thickness, spreading angle and strength of the shear layer exerts little effects on the refracted region where sound wave nearly vertical incident, while mainly influence the corresponding up/downstream region in terms of phase change. Increment of thickness, spreading angle and strength of the shear layer increases the acoustic difference between the shear layer with and without thickness, and produces a larger error of source localization downstream of the actual position.
Key words: aeroacoustics / wind tunnel / shear layer / refraction / source localization
关键字 : 气动声学 / 风洞 / 剪切层 / 折射 / 声源定位
© 2019 Journal of Northwestern Polytechnical University. All rights reserved.
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