## Abstract

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 v^{2}(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 v^{2} goes as k ^{-5/3} at high Reynolds numbers, thereby supporting the sweeping hypothesis.

Original language | English (US) |
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Pages (from-to) | 81-83 |

Number of pages | 3 |

Journal | Physics of Fluids A |

Volume | 2 |

Issue number | 1 |

DOIs | |

State | Published - Jan 1 1990 |

## ASJC Scopus subject areas

- Engineering(all)