Fan Trailing-Edge Noise Prediction Using RANS Simulations

Rozenberg, Yannick; Moreau, Stéphane; Henner, Manuel; Morris, Scott

doi:10.2514/6.2010-3720

Cited by 12 publications

(11 citation statements)

References 23 publications

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“…An extension of this approach to rotating blades is proposed by Rozenberg. 17 The source terms σ given by Eq. (5), (6) and (7) for the different noise terms depend on the following parameters:…”

Section: Ia5 Source Terms and Chordwise Integralsmentioning

confidence: 99%

Similarities of the free-field and in-duct formulations in rotor noise problems

Moreau

Guérin

2011

17th AIAA/CEAS Aeroacoustics Conference (32nd AIAA Aeroacoustics Conference)

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This paper deals with the comparison between open rotor and ducted fan noise. Similar theoretical formulations for the free-field and in-duct noise problems are derived from the original equation for noise generation given by Goldstein. 1 The form of the final equations enables to separate the terms related to noise propagation from those representing the acoustic source. Among the similarities shared by the free-field and in-duct cases, the possibility to define a common cut-off ratio for the spinning modes provides some insight in the relation between the position of the sources and the excited modes in a way more general than that already proposed by the authors. 2 With help of this formalism we hope to reach a better understanding of the differences in noise levels to be expected on contrarotating open rotor (CROR) and contra-rotating turbofan (CRTF) concepts.

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Section: Ia5 Source Terms and Chordwise Integralsmentioning

confidence: 99%

Similarities of the free-field and in-duct formulations in rotor noise problems

Moreau

Guérin

2011

17th AIAA/CEAS Aeroacoustics Conference (32nd AIAA Aeroacoustics Conference)

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“…38 Since the present model is to be applied in test cases for which only few external and no internal parameters may be known, the latter models cannot be applied. However, as mentioned for instance by Rozenberg et al 39 an adverse pressure gradient may induce an increase of as much as 10 dB of the normalized wall pressure spectra. Besides, blades are often subjected to adverse gradient in a turbomachinery.…”

Section: Vb Blade Surface Pressure Spectrum and Blade Response Funcmentioning

confidence: 96%

Acoustic analogy in swirling mean flow applied to predict rotor trailing-edge noise

Posson

Peake

2012

18th AIAA/CEAS Aeroacoustics Conference (33rd AIAA Aeroacoustics Conference)

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The present study aims at accounting for swirling mean flow effects on rotor trailingedge noise. Indeed, the mean flow in between the rotor and the stator of the fan or of a compressor stage is highly swirling. The extension of Ffowcs-Williams & Hawkings' acoustic analogy in a medium at rest with moving surfaces and of Goldstein's acoustic analogy in a circular duct with uniform mean flow to a swirling mean flow in an annular duct is introduced. It is first applied to tonal noise. In most cases, the swirl modifies the pressure distribution downstream of the fan. In several configurations, when the swirl is rather close to a solid body swirl, it is often sufficient to apply a simple Doppler effect correction when predicting the duct modes in uniform mean flow in order to predict accurately the noise radiated with swirl. However, in other realistic configurations, the swirling meanflow effect cannot be addressed using this simple Doppler effect correction. Second, a rotor trailing-edge noise model accounting for both the effects of the annular duct and the swirling mean flow is developed and applied to a realistic fan rotor with different swirling and sheared mean flows (and as a result different associated blade stagger angles). The benchmark cases are built from the Boeing 18-inch Fan Rig Broadband Noise Test. In all cases the swirling mean flow has an effect. In some cases the a simple Doppler effect may address it, but, in other realistic configurations our acoustic analogy with swirl is needed. NomenclatureLatin characters A, D, M differential operators involved in Eq. (7) B blades number B m swirling mean flow factor in the duct wall boundary condition c 0 (r) non-dimensional local base-flow speed of sound c * 0 (R T ) base-flow speed of sound at R T c d0 (r) blade chord length at constant radius r C k numerical integration contour in the complex k plane C ± m,µ duct mode (m, µ) normalization factor D 0 /Dt base-flow time convective derivative E * energy per volume unit [kg.m −1 .s −2 ] E * S energy loss per time and volume unit [kg.function that defines the surface and the fluid locations F 6 th order partial differential non-dimensional operator acting on p F * ± m,µ (ω) duct mode acoustic power factor [kg −1 .m 4 .s 2 ] F * ± m,µ,U nif (ω) duct mode acoustic power factor in uniform mean flow [kg −1 .m 4 .s 2 ] G Green's function tailored to the rigid straight annular duct with swirling mean flowGreen's function tailored to the rigid straight annular duct with uniform mean flow G m time and axial Fourier transform of the m th azimuthal Fourier series component of G h non-dimensional hub radius, i.e. hub-to-tip ratio H(f ) Heaviside functionnon-dimensional axial wave-number of the sonic and nearly-convected modes k ± m,µ,cd non-dimensional chordwise wave-number of the sonic modes K (k, r 0 ) Kernel function that defines the modal eigenvalues k z cd,0 non-dimensional spanwise wavenumber L non-dimensional linearized operator acting on the perturbations L loading-noise source tensor l r non-dimensional spanwise...

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“…7,11,38 It first consists in a RANS CFD computation around the considered airfoil taking into account possible additional effects as the jet deflection due to the profile iself. The boundary-layer data are then extracted near the trailing edge, and a wall-pressure reconstruction model 32, 39 is used to obtain the wall pressure spectrum.…”

Section: Ivb Numerical Setupmentioning

confidence: 99%

Experimental Validation of a Semi-Analytical Trailing-Edge Noise Model Including Broadband Scattering

Christophe

Kucukcoskun

Schram

et al. 2015

21st AIAA/CEAS Aeroacoustics Conference

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In most of industrial applications of rotating machines, the acoustic scattering by surrounding surfaces should be taken into account, as for cooling fans placed on the back of a cooling unit or aircraft Environmental Control Systems (ECS) fan located in a duct. The present paper proposes to combine an extension of Amiet's theory for trailing-edge noise with a BEM solver. The method is validated on an airfoil test case, investigated experimentally at the Université de Sherbrooke, in which a scattering plate is used as complementary scattering surface. The necessary inputs for Amiet's theory are obtained using a RANS computation of the test setup, from which the trailing-edge wall-pressure spectrum is reconstructed using a stochastic model. The comparison of the experimental results with the numerical method proves the necessity to take surrounding surfaces such as support plates into account as scattering objects. Then, the effect of the extra scattering plate is correctly reproduced compared to the free-field prediction, except in the low frequency range, where other sound mechanisms are probably neglected in the present approach.

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Fan Trailing-Edge Noise Prediction Using RANS Simulations

Cited by 12 publications

References 23 publications

Similarities of the free-field and in-duct formulations in rotor noise problems

Similarities of the free-field and in-duct formulations in rotor noise problems

Acoustic analogy in swirling mean flow applied to predict rotor trailing-edge noise

Experimental Validation of a Semi-Analytical Trailing-Edge Noise Model Including Broadband Scattering

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