Numerical Investigation of the Micro-Jets Efficiency for Jet Noise Reduction

Huet, Maxime; Fayard, Benoit; Rahier, Gilles; Vincent, François

doi:10.2514/6.2009-3127

Cited by 21 publications

(11 citation statements)

References 3 publications

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“…To end, computed spectra and integrated pressure levels are azimuthally averaged over 48 microphones located around the jet axis. In the present case of an axisymmetric geometry, far field noise is indeed expected to be statistically independent of the azimuth, which is not the case for short-time duration computed signals and can lead to differences of almost 2 dB (Huet et al, 2009). …”

Section: Noise Radiationmentioning

confidence: 99%

Simulation of Flow Control with Microjets for Subsonic Jet Noise Reduction

Huet¹,

Rahier²,

Vincent³

2012

Applied Aerodynamics

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Section: Noise Radiationmentioning

confidence: 99%

Simulation of Flow Control with Microjets for Subsonic Jet Noise Reduction

Huet¹,

Rahier²,

Vincent³

2012

Applied Aerodynamics

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“…The simulation was run at a Reynolds number of 1 × 10 5 with 18 microjets surrounding the nozzle. Grid refinement in the region of the microjets resulted in 20 cells across each microjet, significantly finer resolution than Huet et al 8 It is worth noting that as a result of using LBM-LES, the jet plume in their simulation has a distinct non-circular shape in both the clean nozzle and microjet simulations.…”

Section: Introductionmentioning

confidence: 99%

“…However, the noise reduction caused by continuous microjets was found to be about 1.5 dB for sideline noise, which agrees well with experimental results. 8 It is possible that the discrepancy in the acoustic predictions is the result of the MILES approach and the noise reduction found in their simulations is the result of the microjets shifting part of the noise spectrum to higher frequencies. These higher frequencies are unable to be properly resolved by an excessively coarse grid coupled with the MILES scheme, thus causing the noise to be dissipated by the solver.…”

Section: Introductionmentioning

confidence: 99%

“…The Reynolds numbers of the main jet in the isothermal and hot simulations were 1.0 × 10 6 and 3.2 × 10 5 , respectively. The simulation technique used by Huet et al 8 was the Monotonically Integrated Large Eddy Simulation (MILES) approach, in which no subgrid model is used. In their simulations, they used 12 microjets, with the inflow boundary conditions for each microjet being applied to one hexahedral cell.…”

Section: Introductionmentioning

confidence: 99%

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Large Eddy Simulation of High Reynolds Number Jets with Microjet Injection

Rife

2011

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

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“…Huet et al 6 performed a numerical study of continuous and pulsed microjets on hot and cold jets. Using the Monotonically Integrated Large Eddy Simulation (MILES) approach, they simulated a cold Mach 0.9 jet with a Reynolds number of 1.0 × 10 6 and a Mach 0.64 hot jet with a Reynolds number of 3.2 × 10 5 .…”

Section: Introductionmentioning

confidence: 99%

High Resolution Simulations of High Reynolds Number Jets with Microjet Injection

Rife¹,

Page²

2013

19th AIAA/CEAS Aeroacoustics Conference

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Large eddy simulations have been performed of a Mach 0.9 jet at a Reynolds number of 1.3 million for both a clean and microjet injected configurations. Two numerical grids were used for the simulations differing in the number of azimuthal cells. The first with 720 cells and an azimuthal clustering near the microjet injection locations, and the other with 1440 cells and a uniform azimuthal cell spacing that matches the finest cell for the clustered case. The grids contained 100 million and 200 million cells respectively. A standard Smagorinsky sub-grid scale model was used together with a synthetic trip in the nozzle shear layer. The non-uniform grid with 720 cells azimuthally showed a variation in laminar to turbulent transition location that was a function of the clustering, with later transition in the coarser regions. However, this had little detrimental impact on mean velocity distributions further downstream. The results of the simulations were compared with PIV experimental data and good agreement of mean radial velocity and turbulent kinetic energy profiles were obtained. The microjets caused a deformation of the shear layer, reducing the radial location of peak turbulence kinetic energy in-line with the microjets. Additionally, the shear layer is translated away from the jet centreline between the microjets and becomes flat in the regions between the microjets. A Ffowcs Williams-Hawking technique was used to propagate the unsteady pressure fluctuations to the far-field. Spectral data at downstream and sideline observer locations indicated the presence of a high-frequency peak in the microjet case which is consistent with the size of the microjets. The microjets provide a blockage effect to the main jet and the peak is probably a shedding like behaviour. Overprediction of overall sound pressure levels by 6-8 dB was found when compared to the experimental data, however, the correct behaviour with observer angle was captured and more importantly the microjets showed a reduction in OASPL of around 2 dB across a range of angles, similar to the experiment results.

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Numerical Investigation of the Micro-Jets Efficiency for Jet Noise Reduction

Cited by 21 publications

References 3 publications

Simulation of Flow Control with Microjets for Subsonic Jet Noise Reduction

Simulation of Flow Control with Microjets for Subsonic Jet Noise Reduction

Large Eddy Simulation of High Reynolds Number Jets with Microjet Injection

High Resolution Simulations of High Reynolds Number Jets with Microjet Injection

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