Modelling boundary layer effects in ActranTM for tonal sound propagation in turbofan intakes
Modelling boundary layer effects in ActranTM for tonal sound propagation in turbofan intakes
ACTRAN TM has been successfully used for predicting fan noise propagation and radiation for turbofan engine intakes and bypass ducts over many years at ISVR. ACTRAN TM predictions generally achieve good agreement with test data, particularly for hard-walled cases, when non-linear propagation effect is not significant. The predictions for lined cases are, however, often lower than measurements, in other words, noise attenuation by acoustic liners tends to be over-predicted.
Acoustic liners in the presence of flow are modelled through Myers impedance boundary condition in ACTRAN TM. An infinitely thin boundary layer assumed in this condition causes instability problem in time domain analysis, but it is not an issue for frequency-domain analysis such as ACTRAN TM. The ease of using impedance boundary condition is one of advantages of frequency-domain analysis, but it has been suspected that not having finite thickness boundary layer might be contributing to the over-prediction of the attenuation by the liners.
The aim of this study is to investigate the impact of a finite thickness boundary layer on the noise attenuation by acoustic liners predicted by using ACTRAN TM models. A uniform duct model with simplified flow is used in the current work.
Turbofan engine noise, Aircraft noise, Acoustics, Aeroacoustics, acoustic liner, shear flow, computational aeroacoustics (CAA), ACTRAN, PREDICTION, noise attenuation
Sugimoto, Rie
cb8c880d-0be0-4efe-9990-c79faa8804f0
October 2018
Sugimoto, Rie
cb8c880d-0be0-4efe-9990-c79faa8804f0
Sugimoto, Rie
(2018)
Modelling boundary layer effects in ActranTM for tonal sound propagation in turbofan intakes.
FFT Acoustic Simulation Conference 2018: Actran Users' Meeting, Radisson Blu Hotel, Toulouse, France.
10 - 11 Oct 2018.
28 pp
.
Record type:
Conference or Workshop Item
(Other)
Abstract
ACTRAN TM has been successfully used for predicting fan noise propagation and radiation for turbofan engine intakes and bypass ducts over many years at ISVR. ACTRAN TM predictions generally achieve good agreement with test data, particularly for hard-walled cases, when non-linear propagation effect is not significant. The predictions for lined cases are, however, often lower than measurements, in other words, noise attenuation by acoustic liners tends to be over-predicted.
Acoustic liners in the presence of flow are modelled through Myers impedance boundary condition in ACTRAN TM. An infinitely thin boundary layer assumed in this condition causes instability problem in time domain analysis, but it is not an issue for frequency-domain analysis such as ACTRAN TM. The ease of using impedance boundary condition is one of advantages of frequency-domain analysis, but it has been suspected that not having finite thickness boundary layer might be contributing to the over-prediction of the attenuation by the liners.
The aim of this study is to investigate the impact of a finite thickness boundary layer on the noise attenuation by acoustic liners predicted by using ACTRAN TM models. A uniform duct model with simplified flow is used in the current work.
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FFT_2018_Acoustic_Simulation_Conference_ISVR_BL_Effects_ActranTM
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Accepted/In Press date: October 2018
Published date: October 2018
Additional Information:
Presentation only
Venue - Dates:
FFT Acoustic Simulation Conference 2018: Actran Users' Meeting, Radisson Blu Hotel, Toulouse, France, 2018-10-10 - 2018-10-11
Keywords:
Turbofan engine noise, Aircraft noise, Acoustics, Aeroacoustics, acoustic liner, shear flow, computational aeroacoustics (CAA), ACTRAN, PREDICTION, noise attenuation
Identifiers
Local EPrints ID: 426735
URI: http://eprints.soton.ac.uk/id/eprint/426735
PURE UUID: b38304fa-ccbf-42ef-816d-eb5a766f008e
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Date deposited: 11 Dec 2018 17:30
Last modified: 16 Mar 2024 03:36
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