High-resolution continuous scan acoustical holography applied to high-speed jet noise

Håvard Vold, Parthiv N. Shah, Joshua Davis, Paul G. Bremner, Dennis McLaughlin, Philip John Morris, Jeremy Veltin, Richard McKinley

Research output: Chapter in Book/Report/Conference proceedingConference contribution

21 Citations (Scopus)

Abstract

Acoustical holography is a technique that has been used extensively to characterize the surface velocities and acoustic pressures of coherently vibrating structures such as engines and gearboxes. For aeroacoustic noise sources such as jets with multiple distributed, partially correlated source mechanisms, scan-based techniques using reference and response transducers and singular value decomposition (SVD) have been applied to acoustical holography to decompose these noise sources into partial fields. Partial fields can reconstruct an overall sound field and also provide a near-field representation of the source that may aid in understanding the physics of jet noise. This paper presents model-scale experimental evidence that advanced signal processing techniques can enable the generation of high resolution acoustical holograms of the hydrodynamic and acoustic near-fields of high-speed jets with a reasonable number of microphones. Two key innovations discussed in the paper are: (1) the construction of partial fields using continuously moving response (i.e., "hologram") microphones and spatially fixed reference microphones with Chebyshev-spaced sampling points to achieve sufficient averaging, and (2) the computation of transfer functions using a method of canonical coherences. This method uses a tensorial formulation of coherence analysis to filter off all signal components at or below the noise floor. The current experimental evidence is to be used in the development of a full-scale acoustical holography system to be demonstrated on a military jet aircraft.

Original languageEnglish (US)
Title of host publication16th AIAA/CEAS Aeroacoustics Conference (31st AIAA Aeroacoustics Conference)
StatePublished - Dec 6 2010
Event16th AIAA/CEAS Aeroacoustics Conference (31st AIAA Aeroacoustics Conference) - Stockholm, Sweden
Duration: Jun 7 2010Jun 9 2010

Publication series

Name16th AIAA/CEAS Aeroacoustics Conference (31st AIAA Aeroacoustics Conference)

Other

Other16th AIAA/CEAS Aeroacoustics Conference (31st AIAA Aeroacoustics Conference)
CountrySweden
CityStockholm
Period6/7/106/9/10

Fingerprint

acoustical holography
jet aircraft noise
Holography
Microphones
microphones
high speed
Holograms
high resolution
Acoustics
Jet aircraft
Aeroacoustics
Military aircraft
near fields
jet aircraft
Acoustic fields
Singular value decomposition
military aircraft
transmissions (machine elements)
Acoustic noise
aeroacoustics

All Science Journal Classification (ASJC) codes

  • Aerospace Engineering
  • Acoustics and Ultrasonics

Cite this

Vold, H., Shah, P. N., Davis, J., Bremner, P. G., McLaughlin, D., Morris, P. J., ... McKinley, R. (2010). High-resolution continuous scan acoustical holography applied to high-speed jet noise. In 16th AIAA/CEAS Aeroacoustics Conference (31st AIAA Aeroacoustics Conference) [2010-3754] (16th AIAA/CEAS Aeroacoustics Conference (31st AIAA Aeroacoustics Conference)).
Vold, Håvard ; Shah, Parthiv N. ; Davis, Joshua ; Bremner, Paul G. ; McLaughlin, Dennis ; Morris, Philip John ; Veltin, Jeremy ; McKinley, Richard. / High-resolution continuous scan acoustical holography applied to high-speed jet noise. 16th AIAA/CEAS Aeroacoustics Conference (31st AIAA Aeroacoustics Conference). 2010. (16th AIAA/CEAS Aeroacoustics Conference (31st AIAA Aeroacoustics Conference)).
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title = "High-resolution continuous scan acoustical holography applied to high-speed jet noise",
abstract = "Acoustical holography is a technique that has been used extensively to characterize the surface velocities and acoustic pressures of coherently vibrating structures such as engines and gearboxes. For aeroacoustic noise sources such as jets with multiple distributed, partially correlated source mechanisms, scan-based techniques using reference and response transducers and singular value decomposition (SVD) have been applied to acoustical holography to decompose these noise sources into partial fields. Partial fields can reconstruct an overall sound field and also provide a near-field representation of the source that may aid in understanding the physics of jet noise. This paper presents model-scale experimental evidence that advanced signal processing techniques can enable the generation of high resolution acoustical holograms of the hydrodynamic and acoustic near-fields of high-speed jets with a reasonable number of microphones. Two key innovations discussed in the paper are: (1) the construction of partial fields using continuously moving response (i.e., {"}hologram{"}) microphones and spatially fixed reference microphones with Chebyshev-spaced sampling points to achieve sufficient averaging, and (2) the computation of transfer functions using a method of canonical coherences. This method uses a tensorial formulation of coherence analysis to filter off all signal components at or below the noise floor. The current experimental evidence is to be used in the development of a full-scale acoustical holography system to be demonstrated on a military jet aircraft.",
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Vold, H, Shah, PN, Davis, J, Bremner, PG, McLaughlin, D, Morris, PJ, Veltin, J & McKinley, R 2010, High-resolution continuous scan acoustical holography applied to high-speed jet noise. in 16th AIAA/CEAS Aeroacoustics Conference (31st AIAA Aeroacoustics Conference)., 2010-3754, 16th AIAA/CEAS Aeroacoustics Conference (31st AIAA Aeroacoustics Conference), 16th AIAA/CEAS Aeroacoustics Conference (31st AIAA Aeroacoustics Conference), Stockholm, Sweden, 6/7/10.

High-resolution continuous scan acoustical holography applied to high-speed jet noise. / Vold, Håvard; Shah, Parthiv N.; Davis, Joshua; Bremner, Paul G.; McLaughlin, Dennis; Morris, Philip John; Veltin, Jeremy; McKinley, Richard.

16th AIAA/CEAS Aeroacoustics Conference (31st AIAA Aeroacoustics Conference). 2010. 2010-3754 (16th AIAA/CEAS Aeroacoustics Conference (31st AIAA Aeroacoustics Conference)).

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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T1 - High-resolution continuous scan acoustical holography applied to high-speed jet noise

AU - Vold, Håvard

AU - Shah, Parthiv N.

AU - Davis, Joshua

AU - Bremner, Paul G.

AU - McLaughlin, Dennis

AU - Morris, Philip John

AU - Veltin, Jeremy

AU - McKinley, Richard

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N2 - Acoustical holography is a technique that has been used extensively to characterize the surface velocities and acoustic pressures of coherently vibrating structures such as engines and gearboxes. For aeroacoustic noise sources such as jets with multiple distributed, partially correlated source mechanisms, scan-based techniques using reference and response transducers and singular value decomposition (SVD) have been applied to acoustical holography to decompose these noise sources into partial fields. Partial fields can reconstruct an overall sound field and also provide a near-field representation of the source that may aid in understanding the physics of jet noise. This paper presents model-scale experimental evidence that advanced signal processing techniques can enable the generation of high resolution acoustical holograms of the hydrodynamic and acoustic near-fields of high-speed jets with a reasonable number of microphones. Two key innovations discussed in the paper are: (1) the construction of partial fields using continuously moving response (i.e., "hologram") microphones and spatially fixed reference microphones with Chebyshev-spaced sampling points to achieve sufficient averaging, and (2) the computation of transfer functions using a method of canonical coherences. This method uses a tensorial formulation of coherence analysis to filter off all signal components at or below the noise floor. The current experimental evidence is to be used in the development of a full-scale acoustical holography system to be demonstrated on a military jet aircraft.

AB - Acoustical holography is a technique that has been used extensively to characterize the surface velocities and acoustic pressures of coherently vibrating structures such as engines and gearboxes. For aeroacoustic noise sources such as jets with multiple distributed, partially correlated source mechanisms, scan-based techniques using reference and response transducers and singular value decomposition (SVD) have been applied to acoustical holography to decompose these noise sources into partial fields. Partial fields can reconstruct an overall sound field and also provide a near-field representation of the source that may aid in understanding the physics of jet noise. This paper presents model-scale experimental evidence that advanced signal processing techniques can enable the generation of high resolution acoustical holograms of the hydrodynamic and acoustic near-fields of high-speed jets with a reasonable number of microphones. Two key innovations discussed in the paper are: (1) the construction of partial fields using continuously moving response (i.e., "hologram") microphones and spatially fixed reference microphones with Chebyshev-spaced sampling points to achieve sufficient averaging, and (2) the computation of transfer functions using a method of canonical coherences. This method uses a tensorial formulation of coherence analysis to filter off all signal components at or below the noise floor. The current experimental evidence is to be used in the development of a full-scale acoustical holography system to be demonstrated on a military jet aircraft.

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M3 - Conference contribution

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Vold H, Shah PN, Davis J, Bremner PG, McLaughlin D, Morris PJ et al. High-resolution continuous scan acoustical holography applied to high-speed jet noise. In 16th AIAA/CEAS Aeroacoustics Conference (31st AIAA Aeroacoustics Conference). 2010. 2010-3754. (16th AIAA/CEAS Aeroacoustics Conference (31st AIAA Aeroacoustics Conference)).