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**Khujadze, George and Nguyen van yen, Romain and Schneider, Kai and Oberlack, Martin and Farge, Marie** (2010):

*Coherent vorticity extraction in turbulent boundary layers using orthogonal wavelets.*

In: Studying Turbulence Using Numerical Simulation Database, In: Center for Turbulence Research, Proceedings of the Summer Program 2010, pp. 87-96, Stanford University/NASA Ames, [Book Section]

## Abstract

High-resolution data obtained by direct numerical simulation of turbulent boundary layers are analysed by means of orthogonal wavelets. The data, originally given on a Chebychev grid, are first interpolated onto an adapted dyadic grid. Then, they are decomposed using a wavelet basis, which accounts for the anisotropy of the flow by using different scales in the wall-normal direction and in the planes parallel to the wall. Thus the vorticity field is decomposed into coherent and incoherent contributions using thresh-olding of the wavelet coefficients. It is shown that less than 1% of the coefficients retain the coherent structures of the flow, while the majority of the coefficients corresponds to a structureless, i.e., noise-like background flow. Scale- and direction-dependent statistics in wavelet space quantify the flow properties at different wall distances.

Item Type: | Book Section |
---|---|

Erschienen: | 2010 |

Creators: | Khujadze, George and Nguyen van yen, Romain and Schneider, Kai and Oberlack, Martin and Farge, Marie |

Title: | Coherent vorticity extraction in turbulent boundary layers using orthogonal wavelets |

Language: | English |

Abstract: | High-resolution data obtained by direct numerical simulation of turbulent boundary layers are analysed by means of orthogonal wavelets. The data, originally given on a Chebychev grid, are first interpolated onto an adapted dyadic grid. Then, they are decomposed using a wavelet basis, which accounts for the anisotropy of the flow by using different scales in the wall-normal direction and in the planes parallel to the wall. Thus the vorticity field is decomposed into coherent and incoherent contributions using thresh-olding of the wavelet coefficients. It is shown that less than 1% of the coefficients retain the coherent structures of the flow, while the majority of the coefficients corresponds to a structureless, i.e., noise-like background flow. Scale- and direction-dependent statistics in wavelet space quantify the flow properties at different wall distances. |

Title of Book: | Center for Turbulence Research, Proceedings of the Summer Program 2010 |

Series Name: | Studying Turbulence Using Numerical Simulation Database |

Number: | XIII |

Publisher: | Stanford University/NASA Ames |

Divisions: | 16 Department of Mechanical Engineering 16 Department of Mechanical Engineering > Fluid Dynamics (fdy) |

Date Deposited: | 02 Sep 2011 13:06 |

Official URL: | http://www.stanford.edu/group/ctr/Summer/SP10/2_04_khujadze.... |

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