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Characterization of SiN Integrated Optical Phased Arrays on a Wafer-Scale Test Station
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Source characterization of full-scale tactical jet noise from phased-array measurements
Blaine M Harker1, Kent L Gee1, Tracianne B Neilsen1
1Department of Physics and Astronomy, Brigham Young University, Provo, Utah 84602, USA.
The Journal of the Acoustical Society of America
|August 3, 2019
Summary
Phased-array algorithms accurately map military aircraft jet noise sources. Source distribution shrinks with higher frequencies and lower engine power, with coherence scaling inversely with engine conditions.
Area of Science:
- Acoustics
- Aerospace Engineering
- Signal Processing
Background:
- Aeroacoustics applications face challenges with distributed sources like jet noise.
- Traditional beamforming methods require adaptation for complex acoustic environments.
- Advances in phased-array algorithms offer new solutions for source identification.
Purpose of the Study:
- To apply advanced phased-array algorithms for equivalent source reconstruction of military aircraft jet noise.
- To analyze the characteristics of jet noise sources under various engine conditions.
- To investigate frequency-dependent source distribution and coherence properties.
Main Methods:
- Utilized a hybrid inverse method combining beamforming with acoustic measurements.
- Employed a 50-element, 30-meter linear array to capture jet noise data.
- Implemented source coherence analysis and array bandwidth extension techniques.
Main Results:
- Equivalent source distributions were successfully reconstructed across different engine conditions.
- Source distribution extent decreased with increasing frequency and decreasing engine power.
- Source coherence lengths scaled inversely with increasing engine conditions.
- Extended array bandwidth beyond the spatial Nyquist frequency limit.
- Directivity analysis showed stationary sideline noise sources near the nozzle and frequency-dependent downstream noise origins.
Conclusions:
- Phased-array beamforming is effective for characterizing complex aeroacoustic sources.
- Jet noise source characteristics are strongly dependent on frequency and engine operating conditions.
- The study provides insights into the spatial and frequency behavior of jet noise.
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