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Subgrid‐scale energy transfer and near‐wall turbulence structure

 

作者: Ugo Piomelli,   Yunfang Yu,   Ronald J. Adrian,  

 

期刊: Physics of Fluids  (AIP Available online 1996)
卷期: Volume 8, issue 1  

页码: 215-224

 

ISSN:1070-6631

 

年代: 1996

 

DOI:10.1063/1.868829

 

出版商: AIP

 

数据来源: AIP

 

摘要:

Conditional averages of the velocity field, subgrid‐scale (SGS) stresses and SGS dissipation are calculated using the velocity fields obtained from the DNS of plane channel flow. The detection criteria isolate the coherent turbulent structures that contribute most strongly to the energy transfer between the large, resolved scales and the subgrid, unresolved, ones. Separate averages are computed for forward and backward scatter. The interscale energy transfer is found to be strongly correlated with the presence of the turbulent structures typical of wall‐bounded flows: quasi‐streamwise and hairpin vortices, sweeps and ejections. In the buffer layer, strong SGS dissipation is observed near lifted shear layers; the forward scatter is associated with ejections, the backscatter with sweeps. Both backward and forward scatter occur in close proximity to longitudinal vortices that form a very shallow angle to the wall. Further away from the solid boundary, in the logarithmic region and beyond, both forward and backward energy transfer are associated prevalently with ejections. Eddy viscosity models do not predict the three‐dimensional structure of these events adequately, while scale‐similar models reproduce the correlation between the large‐scale coherent structures and the SGS events more accurately. ©1996 American Institute of Physics.

 

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