On the departure of near-wall turbulence from the quasi-steady state
File(s)QS_T000_review(1).pdf (9.92 MB)
Accepted version
Author(s)
Agostini, Lionel
Leschziner, Michael
Type
Journal Article
Abstract
An examination is undertaken of the validity and limitations of the quasi-steady hypothesis of near-wall turbulence. This hypothesis is based on the supposition that the statistics of the turbulent fluctuations are universal if scaled by the local, instantaneous, wall shear when its variations are determined from footprints of large-scale, energetic, structures that reside in the outer part of the logarithmic layer. The examination is performed with the aid of direct numerical simulation data for a single Reynolds number, which are processed in a manner that brings out the variability of locally scaled statistics when conditioned on the local value of the wall friction. The key question is to what extent this variability is insignificant, thus reflecting universality. It is shown that the validity of the quasi-steady hypothesis is confined, at best, to a thin layer above the viscous sublayer. Beyond this layer, substantial variations in the conditioned shear-induced production rate of large-scale turbulence cause substantial departures from the hypothesis. Even within the wall-proximate layer, moderate departures are provoked by large-scale distortions in the conditioned strain rate that result in variations in small-scale production of turbulence down to the viscous sublayer.
Date Issued
2019-07-25
Date Acceptance
2019-05-06
Citation
Journal of Fluid Mechanics, 2019, 871, pp.1-12
ISSN
0022-1120
Publisher
Cambridge University Press
Start Page
1
End Page
12
Journal / Book Title
Journal of Fluid Mechanics
Volume
871
Copyright Statement
© 2019 Cambridge University Press. This article has been published in a revised form in Journal of Fluid Mechanics https://doi.org/10.1017/jfm.2019.395. This version is free to view and download for private research and study only. Not for re-distribution, re-sale or use in derivative works.
Sponsor
Commission of the European Communities
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000468628100001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Grant Number
690623
Subjects
Science & Technology
Technology
Physical Sciences
Mechanics
Physics, Fluids & Plasmas
Physics
turbulence modelling
turbulent boundary layers
Publication Status
Published
Article Number
ARTN R1
Date Publish Online
2019-05-20