Lucas, D and Caulfield, CP and Kerswell, RR (2017) Layer formation in horizontally forced stratified turbulence: connecting exact coherent structures to linear instabilities. Journal of Fluid Mechanics, 832. pp. 409-437. ISSN 1469-7645

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Abstract

We consider turbulence in a stratified \u2018Kolmogorov\u2019 flow, driven by horizontal shear in the form of sinusoidal body forcing in the presence of an imposed background linear stable stratification in the third direction. This flow configuration allows the controlled investigation of the formation of coherent structures, which here organise the flow into horizontal layers by inclining the background shear as the strength of the stratification is increased. By numerically converging exact steady states from direct numerical simulations of chaotic flow, we show, for the first time, a robust connection between linear theory predicting instabilities from infinitesimal perturbations to the robust finite-amplitude nonlinear layered state observed in the turbulence. We investigate how the observed vertical length scales are related to the primary linear instabilities and compare to previously considered examples of shear instability leading to layer formation in other horizontally sheared flows.

Item Type: Article
Additional Information: This is the accepted author manuscript (AAM). The final published version (version of record) will be available online via Cambridge University Press at https://doi.org/10.1017/jfm.2017.661 - please refer to any applicable terms of use of the publisher.
Uncontrolled Keywords: mechanical engineering, mechanics of materials, condensed matter physics
Subjects: Q Science > QC Physics
Divisions: Faculty of Natural Sciences > School of Computing and Maths
Depositing User: Symplectic
Date Deposited: 13 Sep 2017 09:31
Last Modified: 20 Nov 2017 15:07
URI: http://eprints.keele.ac.uk/id/eprint/4004

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