On the modal distribution for circular and annular ducts
On the modal distribution for circular and annular ducts
Many important areas of aircraft engine noise concern regimes where frequencies are sufficiently high that corresponding approximations can be made. At such frequencies modal populations are high and approximate methods based on modal averaging can be applied. In this paper the normalised variance of the deviation of the modecount from its average value is examined for circular ducts. Periodic orbit theory, first developed in quantum physics, is used to provide a value for this normalised variance is found and compared with numerical predictions. The implications for concentric and eccentric annular
ducts are examined. It is shown that as eccentricity is varied eigenvalues show ‘avoided crossings’.
Wright, M.C.M.
b7209187-993d-4f18-8003-9f41aaf88abf
Morfey, C.L.
d5f9a8d0-7d8a-4915-a522-bf49dee111f2
Yoon, S.H.
15886fe3-f4d5-41b5-9119-7806cdcfed0a
2003
Wright, M.C.M.
b7209187-993d-4f18-8003-9f41aaf88abf
Morfey, C.L.
d5f9a8d0-7d8a-4915-a522-bf49dee111f2
Yoon, S.H.
15886fe3-f4d5-41b5-9119-7806cdcfed0a
Wright, M.C.M., Morfey, C.L. and Yoon, S.H.
(2003)
On the modal distribution for circular and annular ducts.
9th AIAA/CEAS Aeroacoustics Conference and Exhibition, Hilton Head, USA.
12 - 14 May 2003.
5 pp
.
Record type:
Conference or Workshop Item
(Paper)
Abstract
Many important areas of aircraft engine noise concern regimes where frequencies are sufficiently high that corresponding approximations can be made. At such frequencies modal populations are high and approximate methods based on modal averaging can be applied. In this paper the normalised variance of the deviation of the modecount from its average value is examined for circular ducts. Periodic orbit theory, first developed in quantum physics, is used to provide a value for this normalised variance is found and compared with numerical predictions. The implications for concentric and eccentric annular
ducts are examined. It is shown that as eccentricity is varied eigenvalues show ‘avoided crossings’.
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Published date: 2003
Additional Information:
AIAA 2003-3141
Venue - Dates:
9th AIAA/CEAS Aeroacoustics Conference and Exhibition, Hilton Head, USA, 2003-05-12 - 2003-05-14
Identifiers
Local EPrints ID: 10392
URI: http://eprints.soton.ac.uk/id/eprint/10392
PURE UUID: aa11742f-4bcd-421a-955f-ad5a76dcaecc
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Date deposited: 06 Feb 2006
Last modified: 11 Jan 2023 02:34
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Contributors
Author:
C.L. Morfey
Author:
S.H. Yoon
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