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Sound radiation from a generic bypass duct with bifurcations

Sound radiation from a generic bypass duct with bifurcations
Sound radiation from a generic bypass duct with bifurcations
The influence of bifurcations in an aero-engine bypass duct on noise radiation was investigated through high-order accurate three-dimensional numerical simulations. The physical process was described by a set of acoustic perturbation equations (APE), with a background mean flow. Four bifurcation arrangements, with an airfoil cross-section, were regularly placed in circumferential direction. Results of the simulations were compared with those of a clean duct case. A circumferential mode of m=12 with radial mode of n=1 and multi-n modes at a source frequency of 1547 Hz were set as acoustic inputs. Acoustic modes interfered with the bifurcations resulting in a doubled circumferential mode pattern in the near field acoustic pressure distribution and slightly stronger sound pressure level behind the bifurcations. Far field noise computations indicated 3.2 dB and 2.0 dB sound pressure level increases for radial mode of n=1 and multi-n modes respectively. The bifurcations did not alter the radiation angle. A comparison was also made between APE and linearlised Euler equations (LEE). Results showed that the APE simulation produced almost identical far field sound prediction to the LEE, with a small difference (< 0.8dB) at the main radiation peak angle.
Chen, X.
1c7ce635-f117-4cb5-8f61-cb6a9b23d8a5
Huang, X.
44c6d7c9-07ca-436c-9cbe-1ba9a2f834f9
Zhang, X.
3056a795-80f7-4bbd-9c75-ecbc93085421
Chen, X.
1c7ce635-f117-4cb5-8f61-cb6a9b23d8a5
Huang, X.
44c6d7c9-07ca-436c-9cbe-1ba9a2f834f9
Zhang, X.
3056a795-80f7-4bbd-9c75-ecbc93085421

Chen, X., Huang, X. and Zhang, X. (2008) Sound radiation from a generic bypass duct with bifurcations. 14th AIAA/CEAS Aeroacoustics Conference. 05 - 07 May 2008. 15 pp .

Record type: Conference or Workshop Item (Paper)

Abstract

The influence of bifurcations in an aero-engine bypass duct on noise radiation was investigated through high-order accurate three-dimensional numerical simulations. The physical process was described by a set of acoustic perturbation equations (APE), with a background mean flow. Four bifurcation arrangements, with an airfoil cross-section, were regularly placed in circumferential direction. Results of the simulations were compared with those of a clean duct case. A circumferential mode of m=12 with radial mode of n=1 and multi-n modes at a source frequency of 1547 Hz were set as acoustic inputs. Acoustic modes interfered with the bifurcations resulting in a doubled circumferential mode pattern in the near field acoustic pressure distribution and slightly stronger sound pressure level behind the bifurcations. Far field noise computations indicated 3.2 dB and 2.0 dB sound pressure level increases for radial mode of n=1 and multi-n modes respectively. The bifurcations did not alter the radiation angle. A comparison was also made between APE and linearlised Euler equations (LEE). Results showed that the APE simulation produced almost identical far field sound prediction to the LEE, with a small difference (< 0.8dB) at the main radiation peak angle.

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Published date: 5 May 2008
Venue - Dates: 14th AIAA/CEAS Aeroacoustics Conference, 2008-05-05 - 2008-05-07
Organisations: Aerodynamics & Flight Mechanics

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Local EPrints ID: 64087
URI: https://eprints.soton.ac.uk/id/eprint/64087
PURE UUID: 0cacff42-157d-46f2-884e-67f0a47b66de

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Date deposited: 01 Dec 2008
Last modified: 13 Mar 2019 20:22

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