Acoustic tones in the near-nozzle region of jets: characteristics and variations between Mach numbers 0.5 and 2

Bogey, Christophe

doi:10.1017/jfm.2021.426

Cited by 48 publications

(119 citation statements)

References 73 publications

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“…The numerical setup is identical to that used in recent LES of subsonic and supersonic, free [18,19], and impinging [12,13] jets. In the simulations, the unsteady compressible Navier-Stokes equations are solved in cylindrical coordinates r; θ; z using an OpenMPbased in-house solver.…”

Section: B Numerical Methodsmentioning

confidence: 99%

“…These waves propagate mostly in the jet column, are organized according to their radial and azimuthal structures, and are defined by specific dispersion relations [49]. Their characteristics have been described for free jets at Mach numbers varying from 0.5 to 2 in various studies [19,47,50,51]. For impinging jets at Mach numbers lower than 2, they were shown to form the upstream part of the feedback loops establishing between the nozzle and the plate [11,12].…”

Section: G Frequency-wavenumber Spectramentioning

confidence: 99%

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Flow and Acoustic Fields of Rocket Jets Impinging on a Perforated Plate

Varé

Bogey

2022

AIAA Journal

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Section: B Numerical Methodsmentioning

confidence: 99%

Section: G Frequency-wavenumber Spectramentioning

confidence: 99%

Flow and Acoustic Fields of Rocket Jets Impinging on a Perforated Plate

Varé

Bogey

2022

AIAA Journal

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“…The numerical set-up is identical to that used in recent LES of subsonic and supersonic, free [13,14] and impinging [8,15] jets. In the simulations, the unsteady compressible Navier-Stokes equations are solved in cylindrical coordinates (r, θ, z) using an OpenMP based in-house solver.…”

Section: B Numerical Methodsmentioning

confidence: 99%

Large-eddy simulations of the flow and acoustic fields of a rocket jet impinging on a perforated plate

Varé

Bogey

2021

Aiaa Aviation 2021 Forum

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Large-eddy simulations (LES) of five overexpanded rocket jets impinging on a plate located at a distance of 30r 0 , where r 0 = D/2 is the nozzle radius, and of the corresponding free jet have been performed. The jets are at an exhaust Mach number of 3.1 and a Reynolds number of 2 × 10 5 . Four plates are perforated with a hole of diameter h = 1.33D, 2D, 3D and 4D, whereas the last one is not, in order to investigate the effects of the hole on the jet flow and acoustic fields. The acoustic levels are highest for the non-perforated plate, and decrease as the hole diameter increases, due to weaker interactions between the jet and the plate. In comparison with the levels of the free jet, they are higher by about 5 dB for the full plate, 4 dB for h = 1.33D and 2D, 3 dB for h = 3D and 2 dB for h = 4D. In the upstream direction, for the free jet, the broadband shock associated noise (BBSAN) is dominant. For the impinging jets, spatial Fourier transforms and two-dimensional spatial correlations show that the main upstream noise component is produced by the impingement of the jet turbulent structures on the plate, and that the reflections of the Mach waves on the plate are negligible. In the downstream direction, for the free jet and down to the plate for the impinging jets, the acoustic field is dominated by Mach waves produced by the convection of the jet coherent structures at a supersonic velocity. Downstream of the plate, sound waves are generated by interactions between the jet flow and the plate.

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“…We consider an isothermal, single-stream round jet at velocity U j = 309 m/s, Mach number M j = 0. and the pipe wall thickness is 0.053D j . This jet has been studied in previous works [18][19][20][21][22].…”

Section: A Jet Flowmentioning

confidence: 99%

Imprint of Vortical Structures on the Near-Field Pressure of a Turbulent Jet

2022

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The distributions of turbulent scales in a Mach 0.9 isothermal round jet are investigated for the purpose of developing linear surface-based models for the noise source that can be informed by a Reynolds-averaged Navier Stokes (RANS) solution of the flow field. The jet is calculated by large-eddy simulation (LES) which enables the computation of two-point space-time correlations throughout the jet and its near acoustic field. Time, length, and convective-velocity scales are examined on the surface of peak Reynolds stress (SPS), representing the location of the most energetic eddies, and on a "radiator surface" at the boundary between the rotational and irrotational fields. The nature of the space-time correlations is different for axial velocity fluctuations and pressure fluctuations. Velocity-based correlations appear to capture localized turbulent events, while pressure-based correlations appear dominated by the interaction of large eddies with the surrounding potential flow. The correlation length scales are larger on the radiator surface than on the SPS thus indicating that small-scale eddies do not make a significant imprint on the radiator surface. The scales associated with an emulated RANS solution of the flow are compared to the LES-based scales. Simple relationships are inferred that may aid the development of rapid predictive models.

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Acoustic tones in the near-nozzle region of jets: characteristics and variations between Mach numbers 0.5 and 2

Abstract: Abstract

Cited by 48 publications

References 73 publications

Flow and Acoustic Fields of Rocket Jets Impinging on a Perforated Plate

Flow and Acoustic Fields of Rocket Jets Impinging on a Perforated Plate

Large-eddy simulations of the flow and acoustic fields of a rocket jet impinging on a perforated plate

Imprint of Vortical Structures on the Near-Field Pressure of a Turbulent Jet

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