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Patterns in transitional shear turbulence. Part 2. Emergence and optimal wavelength
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Gomé, Sébastien, Tuckerman, Laurette S. and Barkley, Dwight (2023) Patterns in transitional shear turbulence. Part 2. Emergence and optimal wavelength. Journal of Fluid Mechanics, 964 . A17. doi:10.1017/jfm.2023.289 ISSN 0022-1120.
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Official URL: http://dx.doi.org/10.1017/jfm.2023.289
Abstract
Low Reynolds number turbulence in wall-bounded shear flows en route to laminar flow takes the form of oblique, spatially intermittent turbulent structures. In plane Couette flow, these emerge from uniform turbulence via a spatio-temporal intermittent process in which localised quasi-laminar gaps randomly nucleate and disappear. For slightly lower Reynolds numbers, spatially periodic and approximately stationary turbulent–laminar patterns predominate. The statistics of quasi-laminar regions, including the distributions of space and time scales and their Reynolds-number dependence, are analysed. A smooth, but marked transition is observed between uniform turbulence and flow with intermittent quasi-laminar gaps, whereas the transition from gaps to regular patterns is more gradual. Wavelength selection in these patterns is analysed via numerical simulations in oblique domains of various sizes. Via lifetime measurements in minimal domains, and a wavelet-based analysis of wavelength predominance in a large domain, we quantify the existence and nonlinear stability of a pattern as a function of wavelength and Reynolds number. We report that the preferred wavelength maximises the energy and dissipation of the large-scale flow along laminar–turbulent interfaces. This optimal behaviour is due primarily to the advective nature of the large-scale flow, with turbulent fluctuations playing only a secondary role.
Item Type: | Journal Article | ||||||||
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Subjects: | Q Science > Q Science (General) Q Science > QA Mathematics Q Science > QC Physics T Technology > TA Engineering (General). Civil engineering (General) |
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Divisions: | Faculty of Science, Engineering and Medicine > Science > Mathematics | ||||||||
Library of Congress Subject Headings (LCSH): | Pattern formation (Physical sciences) , Turbulence , Fluid dynamic, Fluid dynamics -- Mathematical models, Shear flow , Fluid mechanics -- Mathematical models, Wavelengths | ||||||||
Journal or Publication Title: | Journal of Fluid Mechanics | ||||||||
Publisher: | Cambridge University Press | ||||||||
ISSN: | 0022-1120 | ||||||||
Official Date: | 10 June 2023 | ||||||||
Dates: |
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Volume: | 964 | ||||||||
Article Number: | A17 | ||||||||
DOI: | 10.1017/jfm.2023.289 | ||||||||
Status: | Peer Reviewed | ||||||||
Publication Status: | Published | ||||||||
Access rights to Published version: | Open Access (Creative Commons) | ||||||||
Date of first compliant deposit: | 30 May 2023 | ||||||||
Date of first compliant Open Access: | 31 May 2023 |
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