Sound radiation from a generic bypass duct with bifurcations

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


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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.

Item Type: Conference or Workshop Item (Paper)
Related URLs:
Subjects: T Technology > TL Motor vehicles. Aeronautics. Astronautics
Divisions : University Structure - Pre August 2011 > School of Engineering Sciences > Aerodynamics & Flight Mechanics
ePrint ID: 64087
Accepted Date and Publication Date:
5 May 2008Published
Date Deposited: 01 Dec 2008
Last Modified: 31 Mar 2016 12:48

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