Numerical Study of the Installed Controlled Diffusion Airfoil at Transitional Reynolds Number

Wu, Hao; Laffay, Paul; Idier, Alexandre; Jaiswal, Prateek; Sanjosé, Marlène; Moreau, Stéphane

doi:10.1007/978-3-319-30379-6_46

Cited by 9 publications

(6 citation statements)

References 9 publications

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“…All RANS simulations have been achieved with ANSYS-CFX or Fluent. The ECL numerical results have been reproduced from Moreau et al 17 The exact UdeS experimental set-up has been reproduced at midspan by Wu et al 33 that also studied the effect of different turbulence models on the results. Good overall agreement is found for all cases except at the trailing edge on the airfoil suction side where the narrower jet-width (13 and 30 cm) experimental results suggest a local flow separation that is not captured by most turbulence models.…”

Section: Wall-pressure Measurementsmentioning

confidence: 94%

“…Wu et al have shown that only the recent transitional models improve the results and show unsteady vortex shedding at the trailing edge. 33 Different noise signatures can then be expected between the three experimental setups. Yet, the overall loading is quite close in the larger nozzle jet widths (30 and 50 cm), and similar overall noise levels can be expected.…”

Section: Wall-pressure Measurementsmentioning

confidence: 99%

“…Two dimensional, two-components Particle Image Velocimetry (PIV) in Wu et al already confirm some of Neal's findings on the wake mean flow profiles. 33 The PSD of the fluctuating velocity signal in the near wake is computed with a time window of 2048 points weighted by a Hanning window and 90 % overlap (Fig. 12).…”

Section: Hot-wire Measurements In the Wake Of The Airfoilmentioning

confidence: 99%

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Detailed experimental investigation of the aeroacoustic field around a Controlled-Diffusion airfoil

Padois

Laffay

Idier

et al. 2015

21st AIAA/CEAS Aeroacoustics Conference

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This study presents the first set of experiments with the Controlled-Diffusion (CD) airfoil in the newly-built anechoic wind-tunnel at Université de Sherbrooke. Velocity measurements in the latter show very uniform mean flow and low turbulence level (0.4 %) up to 56 m/s in the 30 cm square nozzle exit section. Acoustic and velocity measurements have been carried out at several flow velocities and angles of attack. Three distinct flow regimes are observed. At high angle of attack and high velocity the usual broadband noise signature found in the Ecole Centrale de Lyon anechoic wind tunnels is recovered. At low angle of attack, the power spectral density of the microphone signal is dominated by a primary tone with secondary tones, typical of Tollmien-Schlichting noise radiation. This dominant tone is also recovered in the power spectral density of the flow velocity signal. Signal processing tools (spectrogram and bicoherence) are used to investigate the presence of the secondary tones. Two tonal regimes can then be distinguished: one stationnary and one intermittent where some tones disappear intermittently and are formed by a non-linear process. Finally, two parallel microphone arrays associated with high resolution imaging is used to localize the noise sources at the primary tone frequency, which are found at the airfoil trailing edge. At this low frequency, the L1-GIB algorithm is clearly seen more efficient than classical beamforming.

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Section: Wall-pressure Measurementsmentioning

confidence: 94%

Section: Wall-pressure Measurementsmentioning

confidence: 99%

Section: Hot-wire Measurements In the Wake Of The Airfoilmentioning

confidence: 99%

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Detailed experimental investigation of the aeroacoustic field around a Controlled-Diffusion airfoil

Padois

Laffay

Idier

et al. 2015

21st AIAA/CEAS Aeroacoustics Conference

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“…2003; Wu et al. 2016). In the spanwise direction, 96 Fourier modes are employed with 100 % de-aliasing, which corresponds to 194 collocation points in physical space.…”

Section: Comparison Of the Models With Direct Numerical Simulation Anmentioning

confidence: 99%

Analytical models of the wall-pressure spectrum under a turbulent boundary layer with adverse pressure gradient

Grasso

Jaiswal

et al. 2019

J. Fluid Mech.

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This paper presents a comprehensive analytical approach to the modelling of wall-pressure fluctuations under a turbulent boundary layer, unifying and expanding the analytical models that have been proposed over many decades. The Poisson equation governing pressure fluctuations is Fourier transformed in the wavenumber domain to obtain a modified Helmholtz equation, which is solved with a Green’s function technique. The source term of the differential equations is composed of turbulence–mean shear and turbulence–turbulence interaction terms, which are modelled separately within the hypothesis of a joint normal probability distribution of the turbulent field. The functional expression of the turbulence statistics is shown to be the most critical point for a correct representation of the wall-pressure spectrum. The effect of various assumptions on the shape of the longitudinal correlation function of turbulence is assessed in the first place with purely analytical considerations using an idealised flow model. Then, the effect of the hypothesis on the spectral distribution of boundary-layer turbulence on the resulting wall-pressure spectrum is compared with the results of direct numerical simulation computations and pressure measurements on a controlled-diffusion aerofoil. The boundary layer developing over the suction side of this aerofoil in test conditions is characterised by an adverse pressure gradient. The final part of the paper discusses the numerical aspect of wall-pressure spectrum computation. A Monte Carlo technique is used for a fast evaluation of the multi-dimensional integral formulation developed in the theoretical part.

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“…4 (left). The computation is performed at mid-span of the airfoil and the corresponding computational grid is provided by Wu et al 50 and has a total of 69,000 cells. Quadrilateral cells are used to refine the mesh around the nozzle and airfoil surfaces.…”

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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Numerical Study of the Installed Controlled Diffusion Airfoil at Transitional Reynolds Number

Cited by 9 publications

References 9 publications

Detailed experimental investigation of the aeroacoustic field around a Controlled-Diffusion airfoil

Detailed experimental investigation of the aeroacoustic field around a Controlled-Diffusion airfoil

Analytical models of the wall-pressure spectrum under a turbulent boundary layer with adverse pressure gradient

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

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