Time correlations and random sweeping in isotropic turbulence

Mark Nelkin, M. Tabor

Research output: Contribution to journalArticlepeer-review

55 Scopus citations


The Lagrangian and Eulerian frequency spectrum in isotropic turbulence is considered without a mean flow, concentrating on its second moment, the mean-square acceleration. The pressure and viscous contributions are reviewed and the scaling properties of the advective term 〈[(v·∇)v] 2〉 are examined. Random sweeping from this term is shown to be dominant at large Reynolds numbers if the fluctuation spectrum of the kinetic energy v2(x) scales as k -5/3. If on the other hand it satisfies the same Kolmogorov scaling as the pressure going as k -7/3, then the recent renormalization group prediction of no sweeping is recovered. This question is subject to direct experimental resolution. The experiments of Van Atta and Wyngaard [J. Fluid Mech. 72, 673 (1975)] strongly indicate that the spectrum of v2 goes as k -5/3 at high Reynolds numbers, thereby supporting the sweeping hypothesis.

Original languageEnglish (US)
Pages (from-to)81-83
Number of pages3
JournalPhysics of Fluids A
Issue number1
StatePublished - 1990
Externally publishedYes

ASJC Scopus subject areas

  • Engineering(all)


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