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Coherent vorticity extraction in turbulent boundary layers using orthogonal wavelets

Khujadze, George and Nguyen van yen, Romain and Schneider, Kai and Oberlack, Martin and Farge, Marie :
Coherent vorticity extraction in turbulent boundary layers using orthogonal wavelets.
[Online-Edition: http://stacks.iop.org/1742-6596/318/i=2/a=022011]
In: Journal of Physics: Conference Series, 318 (2) 022011/1-022011/10. ISSN 1742-6588
[Article] , (2011)

Official URL: http://stacks.iop.org/1742-6596/318/i=2/a=022011

Abstract

Turbulent boundary layer data computed by direct numerical simulation are analyzed using orthogonal anisotropic wavelets. The flow fields, originally given on a Chebychev grid, are first interpolated on a locally refined 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 thresholding 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: Article
Erschienen: 2011
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:

Turbulent boundary layer data computed by direct numerical simulation are analyzed using orthogonal anisotropic wavelets. The flow fields, originally given on a Chebychev grid, are first interpolated on a locally refined 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 thresholding 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.

Journal or Publication Title: Journal of Physics: Conference Series
Volume: 318
Number: 2
Publisher: Institute of Physics
Divisions: 16 Department of Mechanical Engineering
16 Department of Mechanical Engineering > Fluid Dynamics (fdy)
Date Deposited: 06 Jan 2012 07:29
Official URL: http://stacks.iop.org/1742-6596/318/i=2/a=022011
Additional Information:

13th European Turbulence Conference (ETC13), Warsaw, Poland, 5th - 8th September, 2011

Identification Number: doi:10.1088/1742-6596/318/2/022011
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