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Broadband Acoustic Modal Identification by Array Nonsynchronous Measurements with One Reference

Authors :
Ran Wang
Mingjie Yu
Yue Bai
Liang Yu
Guangming Dong
Source :
AIAA Journal. :1-14
Publication Year :
2023
Publisher :
American Institute of Aeronautics and Astronautics (AIAA), 2023.

Abstract

This paper proposes a broadband acoustic modal identification method based on nonsynchronous measurements from a microphone array, which overcomes the acoustic modal aliasing problem caused by a limited number of microphones. In the proposed method, the number of measurement points is augmented by sequentially rotating a circular microphone array that is circumferentially mounted in the wall of the compressor duct. This technique employs only one reference microphone to enhance the robustness of the cross-spectral matrix completion for nonsynchronous measurements. The fast iterative shrinkage threshold algorithm is adopted to iteratively complete the cross-spectral matrix of all measurement points for acoustic modal identification. The in-duct acoustic modal coefficients of the broadband noise are then determined using the least-squares method with the sound pressure vector recovered from the completed cross-spectral matrix. The accuracy of the cross-spectral matrix and the identified acoustic modals is verified through numerical simulations. The proposed method is validated by experimental results from an axial flow compressor. The results show that it can effectively suppress the modal aliasing problem and identify the azimuthal modes of compressor broadband noise.

Subjects

Subjects :
Aerospace Engineering

Details

ISSN :
1533385X and 00011452
Database :
OpenAIRE
Journal :
AIAA Journal
Accession number :
edsair.doi...........1caf461f6ad1eecd33aa7eefcd305e05
Full Text :
https://doi.org/10.2514/1.j062596