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- L. Biferale
- Università “Tor Vergata,” Dipartimento di Fisica, and , Sezione di Roma II, Via della Ricerca Scientifica 1, I-00133 Roma, Italy
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- G. Boffetta
- Università di Torino Dipartimento di Fisica Generale and INFN, , Via P.Giuria 1, I-10125 Torino, Italy
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- A. Celani
- CNRS , INLN, 1361 Route des Lucioles, F-06560 Valbonne, France
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- B. J. Devenish
- Università “Tor Vergata,” Dipartimento di Fisica, and , Sezione di Roma II, Via della Ricerca Scientifica 1, I-00133 Roma, Italy and , Fitzroy Road, Exeter, Devon EX1 3PB, United Kingdom
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- A. Lanotte
- CNR , ISAC, Str. Prov. Lecce-Monteroni km 1.2, I-73100 Lecce, Italy
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- F. Toschi
- CNR , IAC, Viale del Policlinico 137, I-00161 Roma, Italyand INFN, Sezione di Ferrara, Via G. Saragat 1, I-44100 Ferrara, Italy
説明
<jats:p>We present a detailed investigation of the particle pair separation process in homogeneous isotropic turbulence. We use data from direct numerical simulations up to Rλ∼280 following the evolution of about two million passive tracers advected by the flow over a time span of about three decades. We present data for both the separation distance and the relative velocity statistics. Statistics are measured along the particle pair trajectories both as a function of time and as a function of their separation, i.e., at fixed scales. We compare and contrast both sets of statistics in order to gain insight into the mechanisms governing the separation process. We find very high levels of intermittency in the early stages, that is, for travel times up to order ten Kolmogorov time scales. The fixed scale statistics allow us to quantify anomalous corrections to Richardson diffusion in the inertial range of scales for those pairs that separate rapidly. It also allows a quantitative analysis of intermittency corrections for the relative velocity statistics.</jats:p>
収録刊行物
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- Physics of Fluids
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Physics of Fluids 17 (11), 115101-, 2005-11-01
AIP Publishing