Near-field coherent structures in circular and fractal orifice jets
نویسندگان
چکیده
Near-field coherent structures in turbulent jets from round and square fractal orifices are examined with a Fourier-POD (FPOD) technique at two nozzle diameters the exit. In jet, energy is mostly contained wavenumber $m=0$, associated Kelvin-Helmholtz vortex rings, while jet fundamental azimuthal $m=4$ capture most energy. Nevertheless, radial FPOD profiles nearly insensitive to orifice geometry, forming universal distribution characteristic length scaling. Analysis of near-field fluctuations finds that streamwise vorticity velocity highly coupled by lift-up mechanism both jets.
منابع مشابه
Numerical simulation of vortical flows in the near field of jets from notched circular nozzles
0045-7930/$ see front matter 2009 Elsevier Ltd. A doi:10.1016/j.compfluid.2009.10.006 * Corresponding author. Tel./fax: +1 949 824 1750. E-mail address: [email protected] (F. Liu). The vortex dominated flows in the near field of jets from notched circular nozzles are investigated using direct numerical simulation. The nozzles studied include a normal circular nozzle, a V-shaped notched nozzle, and a...
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ژورنال
عنوان ژورنال: Physical review fluids
سال: 2021
ISSN: ['2469-9918', '2469-990X']
DOI: https://doi.org/10.1103/physrevfluids.6.044612