Stratified Kolmogorov flow. Part 2

Document Type

Article

Publication Date

4-10-2005

Abstract

Forced stratified flows are shown to suffer two types of linear long-wave instability: a 'viscous' instability which is related to the classical instability of Kolmogorov flow, and a 'conductive instability', with the form of a large-scale, negative thermal diffusion. The nonlinear dynamics of both instabilities is explored with weakly nonlinear theory and numerical computations. The introduction of stratification suppresses the viscous instability, but also makes it subcritical. The second instability arises with stronger stratification and creates a prominent staircase in the buoyancy field; the steps of the staircase evolve over long timescales by approaching one another, colliding and merging (coarsening the staircase). © 2005 Cambridge University Press.

Identifier

18144420791 (Scopus)

Publication Title

Journal of Fluid Mechanics

External Full Text Location

https://doi.org/10.1017/S002211200400271X

ISSN

00221120

First Page

23

Last Page

42

Volume

528

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