Intermittency in the relative separations of tracers and of heavy particles in turbulent flows (Articolo in rivista)

Type
Label
  • Intermittency in the relative separations of tracers and of heavy particles in turbulent flows (Articolo in rivista) (literal)
Anno
  • 2014-01-01T00:00:00+01:00 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi
  • 10.1017/jfm.2014.515 (literal)
Alternative label
  • L. Biferale, A. S. Lanotte, R. Scatamacchia and F. Toschi (2014)
    Intermittency in the relative separations of tracers and of heavy particles in turbulent flows
    in Journal of fluid mechanics (Print)
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • L. Biferale, A. S. Lanotte, R. Scatamacchia and F. Toschi (literal)
Pagina inizio
  • 550 (literal)
Pagina fine
  • 572 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume
  • 757 (literal)
Rivista
Note
  • ISI Web of Science (WOS) (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • Department of Physics and INFN, University of Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy CNR-ISAC and INFN-Sez. Lecce, Str. Prov. Lecce-Monteroni, 73100 Lecce, Italy Department of Physics, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands Department of Mathematics and Computer Science, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands CNR-IAC, Via dei Taurini 19, 00185 Rome, Italy (literal)
Titolo
  • Intermittency in the relative separations of tracers and of heavy particles in turbulent flows (literal)
Abstract
  • Results from direct numerical simulations (DNS) of particle relative dispersion in three-dimensional homogeneous and isotropic turbulence at Reynolds number Re?~300 are presented. We study point-like passive tracers and heavy particles, at Stokes number St=0.6,1 and 5. Particles are emitted from localised sources, in bunches of thousands, periodically in time, allowing an unprecedented statistical accuracy to be reached, with a total number of events for two-point observables of the order of 1011. The right tail of the probability density function (PDF) for tracers develops a clear deviation from Richardson's self-similar prediction, pointing to the intermittent nature of the dispersion process. In our numerical experiment, such deviations are manifest once the probability to measure an event becomes of the order of - or rarer than - one part over one million, hence the crucial importance of a large dataset. The role of finite-Reynolds-number effects and the related fluctuations when pair separations cross the boundary between viscous and inertial range scales are discussed. An asymptotic prediction based on the multifractal theory for inertial range intermittency and valid for large Reynolds numbers is found to agree with the data better than the Richardson theory. The agreement is improved when considering heavy particles, whose inertia filters out viscous scale fluctuations. By using the exit-time statistics we also show that events associated with pairs experiencing unusually slow inertial range separations have a non-self-similar PDF. (literal)
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