Neutral Acoustic Wave Modes in Supersonic Impinging Jets

Ferreira, Fabien; Fiore, Maxime; Parisot-Dupuis, Hélène; Gojon, Romain

doi:10.2514/1.j062262

Cited by 3 publications

(3 citation statements)

References 25 publications

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“…2019; Ferreira et al. 2023; Varé & Bogey 2023), showed that the feedback loops are closed, in most cases, by intrinsic modes of the jets, called guided jet modes in recent papers. These modes were first studied in detail by Tam & Hu (1989) using linear stability analyses (LSA) and by modelling jets as vortex sheets of infinite length.…”

Section: Introductionmentioning

confidence: 99%

“…As these large-scale structures interact with the plate or with a standoff shock that may form near the plate, they generate waves that propagate up to the jet nozzle and excite new instability waves in the near-nozzle mixing layers, thus completing the feedback loop. While the upstream part of the feedback loops was initially assumed to be free-stream sound waves (Ho & Nosseir 1981;Powell 1988), Tam & Ahuja (1990) and, afterwards, many authors (Tam & Norum 1992;Panickar & Raman 2007;Gojon, Bogey & Marsden 2016;Bogey & Gojon 2017;Jaunet et al 2019;Ferreira et al 2023;Varé & Bogey 2023), showed that the feedback loops are closed, in most cases, by intrinsic modes of the jets, called guided jet modes in recent papers. These modes were first studied in detail by Tam & Hu (1989) using linear stability analyses (LSA) and by modelling jets as vortex sheets of infinite length.…”

Section: Introductionmentioning

confidence: 99%

“…Some of the guided jet waves (GJWs), called free-stream GJWs (Towne et al 2017;Bogey 2021Bogey , 2022a, propagate upstream at a velocity close to the speed of sound and have significant amplitudes outside the jet column. They are allowed only in narrow frequency bands, in which the tone frequencies obtained in the upstream direction of high subsonic free jets (Schmidt et al 2017;Towne et al 2017;Bogey 2021Bogey , 2022bZaman, Fagan & Upadhyay 2022, in screeching jets (Shen & Tam 2002;Edgington-Mitchell et al 2018Gojon, Bogey & Mihaescu 2018;Mancinelli et al 2019;Nogueira et al 2022), in jets grazing a plate (Jordan et al 2018;Tam & Chandramouli 2020) and in impinging jets (Tam & Norum 1992;Panickar & Raman 2007;Gojon et al 2016;Bogey & Gojon 2017;Jaunet et al 2019;Ferreira et al 2023;Varé & Bogey 2023) fall in most cases.…”

Section: Introductionmentioning

confidence: 99%

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Influence of the boundary-layer thickness on the generation of tonal noise components by subsonic impinging jets

Vincent,

Bogey

2024

J. Fluid Mech.

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The influence of the boundary layer (BL) thickness on the tonal noise generated by subsonic impinging jets is investigated. For that, initially laminar jets at Mach numbers $0.6$ and $0.9$ with BL thicknesses $0.05r_0$ , $0.1r_0$ and $0.2r_0$ , where $r_0$ is the pipe-nozzle radius, impinging on a plate at $6r_0$ from the nozzle, are simulated. For Mach number $0.9$ , acoustic tones due to feedback loops of axisymmetric nature between the nozzle and the plate are generated at frequencies that do not vary with the BL thickness. The two dominant tones are, however, $17$ and $26\ \mathrm {dB}$ stronger for the thickest BL compared with the thinnest one. For Mach number $0.6$ , for the thinnest BL no acoustic peaks appear, as observed in the experiments of the literature, but narrow peaks resulting from axisymmetric feedback loops emerge for thicker BLs. Therefore, low subsonic impinging jets can be resonant for specific nozzle-exit conditions. The increase in tone amplitude for Mach number $0.9$ , and the establishment of feedback loops for Mach number $0.6$ with increasing BL thickness, are found to result from two changes in the jet flow. The first change is that the shear-layer laminar–turbulent transition occurs farther downstream for a thicker BL, leading to a greater predominance of the axisymmetric aerodynamic fluctuations near the plate. The second change is that the amplification of the flow fluctuations between the nozzle and the plate at the tone frequencies is stronger for thicker BLs.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Influence of the boundary-layer thickness on the generation of tonal noise components by subsonic impinging jets

Vincent,

Bogey

2024

J. Fluid Mech.

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Tones and upstream-traveling waves in ideally expanded round impinging jets

Maia,

Fiore,

Gojon

2024

Phys. Rev. Fluids

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Mach Number Dependence of Tone Generation by Impinging Round Jets

Varé

Bogey

2023

AIAA Journal

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The Mach number dependence of tone generation by jets impinging on a plate is investigated using large-eddy simulations, for seven jets at Mach numbers [Formula: see text] between 0.6 and 1.3 and a nozzle-to-plate distance of 8 nozzle radii. For [Formula: see text], the upstream sound radiation is broadband, whereas for [Formula: see text], tones emerge in the near-nozzle spectra, highlighting the establishment of feedback loops. The tone frequencies are consistent with those for aeroacoustic feedback loops between the nozzle and the plate, and exhibit a staging behavior with the Mach number, staying inside or close to the ranges of the upstream-traveling free-stream guided jet waves predicted by a vortex-sheet model. The azimuthal and radial structures of the pressure fields at the tone frequencies agree with those of these waves closing the loops. The selection of the dominant tone and the staging behavior are discussed by evaluating the power gains of the shear-layer instability waves between the nozzle and the plate using linear stability. In most cases, the dominant tones emerge at the possible tone frequencies with the highest gain. For [Formula: see text], the gain of the instability waves at the frequency of the guided jet waves most likely to close feedback mechanisms is lower than the gain peak values, possibly contributing to the absence of resonance.

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Neutral Acoustic Wave Modes in Supersonic Impinging Jets

Cited by 3 publications

References 25 publications

Influence of the boundary-layer thickness on the generation of tonal noise components by subsonic impinging jets

Influence of the boundary-layer thickness on the generation of tonal noise components by subsonic impinging jets

Tones and upstream-traveling waves in ideally expanded round impinging jets

Mach Number Dependence of Tone Generation by Impinging Round Jets

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