Acoustic source distribution on aerofoils and its reconstruction from far-field array measurements
Acoustic source distribution on aerofoils and its reconstruction from far-field array measurements
This paper is concerned with the acoustic source distribution on aerofoils interacting with a turbulent flow. The source distribution is usually taken to be equal to the pressure jump across the aerofoil, whose behaviour is well understood from classical unsteady aerofoil theory. However, much of this source does not radiate to the far-field. This paper deals with the application of Fourier methods to extract the equivalent source distribution on the aerofoil that radiates perfectly to the far-field. This paper shows that, whilst the actual pressure jump across a flat plate tends to infinity at the leading edge while dropping to zero at the trailing edge (due to the Kutta condition), the equivalent source distribution is more uniform across the aerofoil chord, which explains why the radiation spectrum and single-frequency directivity both exhibit strong oscillations due to interference from coherent sources across the chord. A method for extracting this far-field equivalent source distribution from an array of far-field measurements is proposed in this paper.
Aeroacoustics, Aerofoil interaction noise, Microphone arrays, Source reconstruction
Casagrande Hirono, Fabio
ef8c2e33-96ec-467b-874d-74f0f9bb5f09
Joseph, Phillip
9c30491e-8464-4c9a-8723-2abc62bdf75d
Fazi, Filippo
e5aefc08-ab45-47c1-ad69-c3f12d07d807
3 February 2021
Casagrande Hirono, Fabio
ef8c2e33-96ec-467b-874d-74f0f9bb5f09
Joseph, Phillip
9c30491e-8464-4c9a-8723-2abc62bdf75d
Fazi, Filippo
e5aefc08-ab45-47c1-ad69-c3f12d07d807
Casagrande Hirono, Fabio, Joseph, Phillip and Fazi, Filippo
(2021)
Acoustic source distribution on aerofoils and its reconstruction from far-field array measurements.
Journal of Sound and Vibration, 492, [115786].
(doi:10.1016/j.jsv.2020.115786).
Abstract
This paper is concerned with the acoustic source distribution on aerofoils interacting with a turbulent flow. The source distribution is usually taken to be equal to the pressure jump across the aerofoil, whose behaviour is well understood from classical unsteady aerofoil theory. However, much of this source does not radiate to the far-field. This paper deals with the application of Fourier methods to extract the equivalent source distribution on the aerofoil that radiates perfectly to the far-field. This paper shows that, whilst the actual pressure jump across a flat plate tends to infinity at the leading edge while dropping to zero at the trailing edge (due to the Kutta condition), the equivalent source distribution is more uniform across the aerofoil chord, which explains why the radiation spectrum and single-frequency directivity both exhibit strong oscillations due to interference from coherent sources across the chord. A method for extracting this far-field equivalent source distribution from an array of far-field measurements is proposed in this paper.
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Submitted date: 29 April 2020
Accepted/In Press date: 13 October 2020
e-pub ahead of print date: 14 October 2020
Published date: 3 February 2021
Additional Information:
Funding Information:
Fabio Casagrande Hirono would like to thank the National Council for Scientific and Technical Development (Conselho Nacional de Desenvolvimento Científico e Tecnológico - CNPq) of the Federal Government of Brazil for sponsoring his PhD degree under the “Science Without Borders” program.
Funding Information:
Fabio Casagrande Hirono would like to thank the National Council for Scientific and Technical Development (Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq) of the Federal Government of Brazil for sponsoring his PhD degree under the ?Science Without Borders? program.
Publisher Copyright:
© 2020 Elsevier Ltd
Keywords:
Aeroacoustics, Aerofoil interaction noise, Microphone arrays, Source reconstruction
Identifiers
Local EPrints ID: 444664
URI: http://eprints.soton.ac.uk/id/eprint/444664
ISSN: 0022-460X
PURE UUID: c6d33c77-433c-484e-94af-3f9ac37fc002
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Date deposited: 28 Oct 2020 18:05
Last modified: 17 Mar 2024 06:00
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Author:
Fabio Casagrande Hirono
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