|Title:||On the relation between fronts and high-shear layers in wall turbulence|
|Authors :||Wilhelm, Dirk|
|Published in :||Flow, Turbulence and Combustion|
|Publisher / Ed. Institution :||Springer|
|License (according to publishing contract) :||Licence according to publishing contract|
|Type of review:||Peer review (publication)|
|Subjects :||Wall turbulence; Coherent structures; Direct numerical simulation|
|Subject (DDC) :||530: Physics|
|Abstract:||Direct numerical simulation results of turbulent channel flow are analyzed in order to examine the relation between two kinds of near-wall flow structures, namely the instantaneous shear layers and the fronts which are derived from two-point statistics of the streamwise velocity component. The near-wall shear layers are analyzed by flow visualizations and conditional sampling, while the fronts are examined by means of space-time correlations and spatial two-point correlation functions. The present study focuses on the analysis of the propagation speed and the spatial shape of the structures. Concerning the propagation speed it is shown that the results obtained from flow visualizations are in close agreement with the propagation velocities derived from space-time correlation functions. The comparison of VISA results for the instantaneous shear with spatial structures obtained from two-point correlations of the streamwise velocity and the shear gives evidence that the fronts are intimately related to the pronounced near-wall shear layers.|
|Departement:||School of Engineering|
|Publication type:||Article in scientific journal|
|Appears in Collections:||Publikationen School of Engineering|
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