## Abstract

Statistical properties of a coherent structure function F_{CS} are investigated using DNS data for homogeneous isotropic turbulence and turbulent channel flows. The function F_{CS} is defined as the second invariant Q of a velocity gradient tensor normalized by the magnitude E of the velocity gradient tensor. In homogeneous isotropic turbulence, the probability density function (pdf) of F_{CS} shows good agreement at different Reynolds number. The volume fraction of positive Q and the average of F_{CS} converge to a certain value at high Reynolds number. For the turbulent channel flows, the pdf of F_{CS} at different Reynolds number coincides very well at the distance from the wall in wall units. The profiles of the conditional average of positive and negative Q, the volume fraction, and the near-wall F_{CS} ^{2} are in good agreement at different Reynolds number and those profiles are given as a function of the distance from the wall in wall units.

Original language | English |
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Pages | 335-340 |

Number of pages | 6 |

Publication status | Published - 2009 Jan 1 |

Event | 6th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2009 - Seoul, Korea, Republic of Duration: 2009 Jun 22 → 2009 Jun 24 |

### Other

Other | 6th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2009 |
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Country | Korea, Republic of |

City | Seoul |

Period | 09/6/22 → 09/6/24 |

## ASJC Scopus subject areas

- Fluid Flow and Transfer Processes