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Presence and properties of acoustic peaks near the nozzle of impinging rocket jets

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  • Additional Information
    • Contributors:
      Laboratoire de Mecanique des Fluides et d'Acoustique (LMFA); École Centrale de Lyon (ECL); Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL); Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon); Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS); ANR-10-EQPX-0029,EQUIP@MESO,Equipement d'excellence de calcul intensif de Mesocentres coordonnés - Tremplin vers le calcul petaflopique et l'exascale(2010); ANR-10-LABX-0060,CeLyA,Lyon Acoustics Centre(2010); ANR-16-IDEX-0005,IDEXLYON,IDEXLYON(2016)
    • Publication Information:
      CCSD
      EDP Sciences
    • Publication Date:
      2022
    • Collection:
      HAL Lyon 1 (University Claude Bernard Lyon 1)
    • Abstract:
      International audience ; The presence and properties of acoustic peaks near the nozzle of impinging rocket jets have been investigated. Four jets at a Mach number of 3.1 impinging on a plate at a distance L = 15r0 , 20r0 , 25r0 and 30r0 from the nozzle, where r0 is the nozzle radius, have been computed using large-eddy simulations. In all cases, upstream-travelling pressure waves are generated by the jet impingement on the plate, with amplitudes decreasing with the nozzle-to-plate distance. The near-nozzle pressure spectra contain peaks, at frequencies not varying much with this distance. For L >= 20r0 , the spectra are dominated by a low-frequency peak, whereas two additional high-frequency peaks emerge for L = 15r0. The low-frequency peak is associated with the azimuthal mode ntheta = 0, whereas the two other ones are due to strong components for modes ntheta >= 1. As for near-nozzle tones for free and impinging jets at lower Mach numbers, the peak frequencies fall close to the frequency bands of the upstream-propagating guided jet waves, showing a link between the peaks and the latter waves. Regarding the peak levels, they do not change significantly with the nozzle-to-plate distance for the low-frequency peak, but they decrease by 1.5 to 18 dB as the distance increases for the other peaks. Finally, for L >= 20r 0 , the near-nozzle peak frequency is close to that of the strongest shear-layer structures, indicating a connexion between the upstream noise and these structures. For L = 15r0 , a shock-leakage mechanism of a near-plate shock is found to generate the upstream noise.
    • Accession Number:
      10.1051/aacus/2022033
    • Online Access:
      https://hal.science/hal-03761415
      https://hal.science/hal-03761415v1/document
      https://hal.science/hal-03761415v1/file/vare_acta2022.pdf
      https://doi.org/10.1051/aacus/2022033
    • Rights:
      info:eu-repo/semantics/OpenAccess
    • Accession Number:
      edsbas.A3F94892