Spectral analysis of near-wall turbulence in channel flow at Re-tau=4200 with emphasis on the attached-eddy hypothesis
File(s)AE_review_v5.pdf (18.76 MB)
Accepted version
Author(s)
Agostini, L
Leschziner, M
Type
Journal Article
Abstract
Direct numerical simulation data for channel flow at a friction Reynolds number of 4200, generated by Lozano-Durán and Jiménez [J. Fluid Mech. 759, 432 (2014)], are used to examine the properties of near-wall turbulence within subranges of eddy-length scale. Attention is primarily focused on the intermediate layer (mesolayer) covering the logarithmic velocity region within the range of wall-scaled wall-normal distance of 80–1500. The examination is based on a number of statistical properties, including premultiplied and compensated spectra, the premultiplied derivative of the second-order structure function, and three scalar parameters that characterize the anisotropic or isotropic state of the various length-scale subranges. This analysis leads to the delineation of three regions within the map of wall-normal-wise premultiplied spectra, each characterized by distinct turbulence properties. A question of particular interest is whether the Townsend-Perry attached-eddy hypothesis (AEH) can be shown to be valid across the entire mesolayer, in contrast to the usual focus on the outer portion of the logarithmic-velocity layer at high Reynolds numbers, which is populated with very-large-scale motions. This question is addressed by reference to properties in the premultiplied scalewise derivative of the second-order structure function (PMDS2) and joint probability density functions of streamwise-velocity fluctuations and their streamwise and spanwise derivatives. This examination provides evidence, based primarily on the existence of a plateau region in the PMDS2, for the qualified validity of the AEH right down the lower limit of the logarithmic velocity range.
Date Issued
2017-01-18
Date Acceptance
2016-08-01
Citation
Physical Review Fluids, 2017, 2 (1)
ISSN
2469-990X
Publisher
American Physical Society
Journal / Book Title
Physical Review Fluids
Volume
2
Issue
1
Copyright Statement
© 2017 American Physical Society
Sponsor
Commission of the European Communities
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000393752800001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Grant Number
690623
Subjects
Science & Technology
Physical Sciences
Physics, Fluids & Plasmas
Physics
BOUNDARY-LAYERS
PIPE-FLOW
LOGARITHMIC REGION
REYNOLDS-NUMBERS
SCALE STRUCTURES
FLUCTUATIONS
EDDIES
Publication Status
Published
Article Number
ARTN 014603