Turbulent transport for wall shear stress fluctuations
File(s)
Author(s)
Myoungkyu, Lee
Hwang, Yongyun
Type
Journal Article
Abstract
Statistical structure and the underlying energy budget of wall shear stress fluctuations are studied in both Poiseulle and Couette flows with emphasis on its streamwise component. Using a dimensional analysis and direct numerical simulation data, it is shown that the spectra of streamwise wall dissipation for 𝜆 ≲ 1000𝛿𝜈 are asymptotically invariant with the Reynolds number (𝑅𝑒), whereas those for 𝜆 ≳ 𝛿 decay with 𝑅𝑒 (here, 𝜆 is a nominal wall-parallel wavelength, and 𝛿𝜈 and 𝛿 are the viscous inner and outer length scales, respectively). The wall dissipation increases with 𝑅𝑒 due to the increasing contribution of the spectra at 1000𝛿𝜈 ≲ 𝜆 ≲ 𝛿. The subsequent analysis of the energy budget shows that the near-wall motions associated with these wall dissipation spectra are mainly driven by turbulent transport and are ‘inactive’ in the sense that they contain very little Reynolds shear stress (or turbulence production). As such, turbulent transport spectra near the wall are also found to share the
same 𝑅𝑒-scaling behaviour with wall dissipation, and this is observed in the spectra of both the wall-normal and inter-scale turbulent transports. The turbulent transport underpinning the increase of wall dissipation with 𝑅𝑒 is characterised by energy fluxes towards the wall, together with inverse energy transfer from small to large length scales along the wall-parallel directions.
same 𝑅𝑒-scaling behaviour with wall dissipation, and this is observed in the spectra of both the wall-normal and inter-scale turbulent transports. The turbulent transport underpinning the increase of wall dissipation with 𝑅𝑒 is characterised by energy fluxes towards the wall, together with inverse energy transfer from small to large length scales along the wall-parallel directions.
Date Issued
2025-11-25
Date Acceptance
2025-10-15
Citation
Journal of Fluid Mechanics, 2025, 1023
ISSN
0022-1120
Publisher
Cambridge University Press
Journal / Book Title
Journal of Fluid Mechanics
Volume
1023
Copyright Statement
© The Author(s), 2025. Published by Cambridge University Press. This is an Open Access article, distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike licence (https://creativecommons.org/licenses/by-nc-sa/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the same Creative Commons licence is used to distribute the re-used or adapted article and the original article is properly cited. The written permission of Cambridge University Press must be obtained prior to any commercial use.
Identifier
10.1017/jfm.2025.10844
Subjects
turbulence theory
turbulent boundary layers
turbulent flows
Publication Status
Published
Article Number
ARTN A48