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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://www.stanford.edu/group/ctr/Summer/SP10/2_04_khujadze....]
In: Center for Turbulence Research, Proceedings of the Summer Program 2010. Studying Turbulence Using Numerical Simulation Database (XIII). Stanford University/NASA Ames , pp. 87-96.
[Book Section] , (2010)

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

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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