For the prediction of acoustic waves from a rocket plume, Mach number and temperature effects are investigated. Although, the actual rocket plume is of the over-expanded condition, Mach number and temperature effects of ideally expanded supersonic jets are analyzed because the Mach wave does not depends on the nozzle design Mach number, see reference (Nonomura and Fujii, AIAA paper 2008-2836). With regard to computation, the seventh order weighted compact non-linear scheme and the tenth order compact scheme are used for the fluid analysis and near fields acoustics propagation, respectively. Totally 9 cases are computed, and then Mach number and temperature effects are discussed. A Mach number effect on the flow field is found to be that the potential core length becomes shorter with increasing Mach number. Mach number effects on the acoustic field are as follows; As the Mach number increases, 1) the sound pressure level becomes higher, 2) the high SPL region of the near field becomes wider, 3) the angle of the direction of maximum acoustic emission becomes larger and 4) the peak Strouhal number becomes lower. A temperature effect on flow-fields is that the potential core becomes shorter with increasing temperature of jet. Temperature effects on acoustics fields are as follows. As the temperature of jet increases, 1) the sound pressure level becomes higher, 2) the high SPL region of the near field becomes slightly wider, 3) the angle of the direction of maximum acoustic emission becomes larger and 4) the peak Strouhal number becomes lower at downstream. Finally these effects are compared. Temperature effects on the direction of the maximum acoustic emission and the peak Strouhal number at downstream seems to be stronger than Mach number effects.
|Journal||Collection of Technical Papers - AIAA Applied Aerodynamics Conference|
|Publication status||Published - 2008 Jan 1|
|Event||26th AIAA Applied Aerodynamics Conference - Honolulu, HI, United States|
Duration: 2008 Aug 18 → 2008 Aug 21
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