## Abstract

The inertial-subrange scaling of the axial velocity component is examined for the centreline of turbulent pipe flow for Reynolds numbers in the range . Estimates of the dissipation rate are made by both integration of the one-dimensional dissipation spectrum and the third-order moment of the structure function. In neither case does the non-dimensional dissipation rate asymptote to a constant; rather than decreasing, it increases indefinitely with Reynolds number. Complete similarity of the inertial range spectra is not evident: there is little support for the hypotheses of Kolmogorov (Dokl. Akad. Nauk SSSR, vol.A 32, 1941a, pp.A 16-18; Dokl. Akad. Nauk SSSR, vol.A 30, 1941b, pp.A 301-305) and the effects of Reynolds number are not well represented by Kolmogorov's 'extended similarity hypothesis' (J. Fluid Mech., vol.A 13, 1962, pp.A 82-85). The second-order moment of the structure function does not show a constant value, even when compensated by the extended similarity hypothesis. When corrected for the effects of finite Reynolds number, the third-order moments of the structure function accurately support the 'four-fifths law', but they do not show a clear plateau. In common with recent work in grid turbulence, non-equilibrium effects can be represented by a heuristic scaling that includes a global Reynolds number as well as a local one. It is likely that non-equilibrium effects appear to be particular to the nature of the boundary conditions. Here, the principal effects of the boundary conditions appear through finite turbulent transport at the pipe centreline, which constitutes a source or a sink at each wavenumber.

Original language | English (US) |
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Pages (from-to) | 602-613 |

Number of pages | 12 |

Journal | Journal of Fluid Mechanics |

Volume | 788 |

DOIs | |

State | Published - Jan 11 2016 |

## All Science Journal Classification (ASJC) codes

- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering
- Applied Mathematics

## Keywords

- isotropic turbulence
- pipe flow boundary layer
- turbulence theory