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| Titel |
Anomalous diffusion in geophysical and laboratory turbulence |
| VerfasserIn |
A. Tsinober |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1023-5809
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| Digitales Dokument |
URL |
| Erschienen |
In: Nonlinear Processes in Geophysics ; 1, no. 2/3 ; Nr. 1, no. 2/3, S.80-94 |
| Datensatznummer |
250000001
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| Publikation (Nr.) |
 copernicus.org/npg-1-80-1994.pdf |
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| Zusammenfassung |
| We present an overview and some new results on anomalous
diffusion of passive scalar in turbulent flows (including those used by Richardson in his
famous paper in 1926). The obtained results are based on the analysis of the properties of
invariant quantities (energy, enstrophy, dissipation, enstrophy generation, helicity
density, etc.) - i.e. independent of the choice of the system of reference as the most
appropriate to describe physical processes - in three different turbulent laboratory flows
(grid-flow, jet and boundary layer, see Tsinober et al. (1992) and Kit et al. (1993). The
emphasis is made on the relations between the asymptotic properties of the intermittency
exponents of higher order moments of different turbulent fields (energy, dissipation,
helicity, spontaneous breaking of isotropy and reflexional symmetry) and the variability
of turbulent diffusion in the atmospheric boundary layer, in the troposphere and in the
stratosphere. It is argued that local spontaneous breaking of isotropy of turbulent flow
results in anomalous scaling laws for turbulent diffusion (as compared to the scaling law
of Richardson) which are observed, as a rule, in different atmospheric layers from the
atmospheric boundary layer (ABL) to the stratosphere. Breaking of rotational symmetry is
important in the ABL, whereas reflexional symmetry breaking is dominating in the
troposphere locally and in the stratosphere globally. The results are of speculative
nature and further analysis is necessary to validate or disprove the claims made, since
the correspondence with the experimental results may occur for the wrong reasons as
happens from time to time in the field of turbulence. |
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