Aeroacoustic source characterisation using inverse methods
Aeroacoustic source characterisation using inverse methods
Measurements of the sound field radiated by aeroacoustic sources, usually acquired at a distance using some form of sensor array, can be used to reconstruct the sources that generated that sound field by using inverse methods. However, many aeroacoustic sources of practical interest are usually distributed in extent and the inverse methods can then only be applied to a discretised representation of the source. For the inversion process to yield a unique solution, the number of observations must be equal to or exceed the number of unknown source elements - the system needs to be square or over-determined, and if the source is large compared to the acoustic wavelength of interest, a prohibitively-large number of sensors is required. In addition, these measurements may be taken in a reverberant environment in the presence of significant air flow. This paper describes the practical application of a technique, known as the "Bounded Correlation Length (BCL) Inverse Method", first described by the authors at ICSV13. This method allows the number of required sensors to be significantly reduced by exploiting the fact that many aeroacoustic source distributions have finite correlation lengths. The BCL Inverse Method is applied to a real aeroacoustic source problem, in a reverberant space, and it is shown that a distributed source divided into 84 source elements can be successfully characterised by using only 20 microphones.
1511-1518
International Institute of Acoustics and Vibration
Nelson, Philip
5c6f5cc9-ea52-4fe2-9edf-05d696b0c1a9
Holland, Keith
90dd842b-e3c8-45bb-865e-3e7da77ec703
November 2015
Nelson, Philip
5c6f5cc9-ea52-4fe2-9edf-05d696b0c1a9
Holland, Keith
90dd842b-e3c8-45bb-865e-3e7da77ec703
Nelson, Philip and Holland, Keith
(2015)
Aeroacoustic source characterisation using inverse methods.
In SOUND AND VIBRATION. INTERNATIONAL CONGRESS. 22ND 2015. (ICSV 22) (8 VOLS).
International Institute of Acoustics and Vibration.
.
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Conference or Workshop Item
(Paper)
Abstract
Measurements of the sound field radiated by aeroacoustic sources, usually acquired at a distance using some form of sensor array, can be used to reconstruct the sources that generated that sound field by using inverse methods. However, many aeroacoustic sources of practical interest are usually distributed in extent and the inverse methods can then only be applied to a discretised representation of the source. For the inversion process to yield a unique solution, the number of observations must be equal to or exceed the number of unknown source elements - the system needs to be square or over-determined, and if the source is large compared to the acoustic wavelength of interest, a prohibitively-large number of sensors is required. In addition, these measurements may be taken in a reverberant environment in the presence of significant air flow. This paper describes the practical application of a technique, known as the "Bounded Correlation Length (BCL) Inverse Method", first described by the authors at ICSV13. This method allows the number of required sensors to be significantly reduced by exploiting the fact that many aeroacoustic source distributions have finite correlation lengths. The BCL Inverse Method is applied to a real aeroacoustic source problem, in a reverberant space, and it is shown that a distributed source divided into 84 source elements can be successfully characterised by using only 20 microphones.
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Published date: November 2015
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Funding Information:
This work was carried out in the UTC in Gas Turbine Noise at ISVR, University of Southampton, and was funded by Rolls-Royce plc. The authors would like to thank Rolls-Royce Deutschland and DLR for their cooperation and assistance.
Copyright:
Copyright 2016 Elsevier B.V., All rights reserved.
Venue - Dates:
22nd International Congress on Sound and Vibration, Florence, Florence, Italy, 2015-07-12 - 2015-07-16
Identifiers
Local EPrints ID: 457661
URI: http://eprints.soton.ac.uk/id/eprint/457661
PURE UUID: 09d1e470-bf6a-4a16-bf7a-698890766b4a
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Date deposited: 14 Jun 2022 16:58
Last modified: 18 Mar 2024 02:31
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Author:
Keith Holland
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