### Abstract

Using measurements of all three components of the temperature dissipation χ in a laboratory boundary layer, the measured probability density p(χ
_{r}) of χ
_{r}, or χ averaged over a distance r, is found to be closely log-normal over a significant range of r. The variance σ
^{2} of lnχ
_{r} follows the relation σ
^{2} = A + μln(L/r), with μ= 0.35, where L is an integral scale of turbulence. High order moments, up to order 5, of χ
_{r} show a power-law variation with r/L. With increasing order of the moment, the power-law exponents become increasingly smaller than the corresponding values implied by assumed log-normality of p(χ
_{r}) but are consistent with the bounds given by Novikov's theory. It is suggested that the observed close agreement with log-normality of p(χ
_{r}) may be misleading when sufficiently high order moments of χ
_{r} are considered.

Original language | English (US) |
---|---|

Pages (from-to) | 1800-1804 |

Number of pages | 5 |

Journal | Physics of Fluids |

Volume | 20 |

Issue number | 11 |

State | Published - 1977 |

### Fingerprint

### ASJC Scopus subject areas

- Condensed Matter Physics
- Physics and Astronomy(all)
- Mechanics of Materials
- Computational Mechanics
- Fluid Flow and Transfer Processes

### Cite this

*Physics of Fluids*,

*20*(11), 1800-1804.

**Log-normality of temperature dissipation in a turbulent boundary layer.** / Antonia, R. A.; Sreenivasan, K. R.

Research output: Contribution to journal › Article

*Physics of Fluids*, vol. 20, no. 11, pp. 1800-1804.

}

TY - JOUR

T1 - Log-normality of temperature dissipation in a turbulent boundary layer

AU - Antonia, R. A.

AU - Sreenivasan, K. R.

PY - 1977

Y1 - 1977

N2 - Using measurements of all three components of the temperature dissipation χ in a laboratory boundary layer, the measured probability density p(χ r) of χ r, or χ averaged over a distance r, is found to be closely log-normal over a significant range of r. The variance σ 2 of lnχ r follows the relation σ 2 = A + μln(L/r), with μ= 0.35, where L is an integral scale of turbulence. High order moments, up to order 5, of χ r show a power-law variation with r/L. With increasing order of the moment, the power-law exponents become increasingly smaller than the corresponding values implied by assumed log-normality of p(χ r) but are consistent with the bounds given by Novikov's theory. It is suggested that the observed close agreement with log-normality of p(χ r) may be misleading when sufficiently high order moments of χ r are considered.

AB - Using measurements of all three components of the temperature dissipation χ in a laboratory boundary layer, the measured probability density p(χ r) of χ r, or χ averaged over a distance r, is found to be closely log-normal over a significant range of r. The variance σ 2 of lnχ r follows the relation σ 2 = A + μln(L/r), with μ= 0.35, where L is an integral scale of turbulence. High order moments, up to order 5, of χ r show a power-law variation with r/L. With increasing order of the moment, the power-law exponents become increasingly smaller than the corresponding values implied by assumed log-normality of p(χ r) but are consistent with the bounds given by Novikov's theory. It is suggested that the observed close agreement with log-normality of p(χ r) may be misleading when sufficiently high order moments of χ r are considered.

UR - http://www.scopus.com/inward/record.url?scp=0002137314&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0002137314&partnerID=8YFLogxK

M3 - Article

VL - 20

SP - 1800

EP - 1804

JO - Physics of Fluids

JF - Physics of Fluids

SN - 1070-6631

IS - 11

ER -