Identification of the acoustic response in the irrotational near-field of an excited subsonic jet

Analysis and understanding of the noise generation processes in high-speed, high-Reynolds number jets are hampered by the broad range of turbulent scales and the disparate fluctuation intensities of the acoustic response hidden under the hydrodynamic source. Towards providing insight into these processes, the irrotational near-field of an unheated, Mach 0.9 jet is decomposed into its constitutive hydrodynamic and acoustic components using three separate filters in the present work. Previous work had decomposed the full near-field pressure signal into its hydrodynamic and acoustic components using a linear filter in Fourier space. The presence of numerical artifacts in the results prompted the current study, in which a new algorithm is developed to filter the pressure field in wavelet space. Results from the new method are then compared against those obtained using the standard Fourier-based algorithm, as well as another algorithm based upon the empirical mode decomposition. The ability of the wavelet-based algorithm to decompose the broadband irrotational pressure field into its constitutive components, as well as to identify and extract individual events, is found to be superior to that of the other two decomposition methods.

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  • English

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  • Accession Number: 01743710
  • Record Type: Publication
  • Files: TRIS
  • Created Date: May 24 2019 4:59PM