Inverse cascade and symmetry breaking in rapidly-rotating Boussinesq convection

Silvers, L. J., Favier, B. & Proctor, M. R. E. (2014). Inverse cascade and symmetry breaking in rapidly-rotating Boussinesq convection. Physics of Fluids, 26, 096605. doi: 10.1063/1.489513

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Abstract

In this paper we present numerical simulations of rapidly-rotating Rayleigh-B\'enard convection in the Boussinesq approximation with stress-free boundary conditions. At moderately low Rossby number and large Rayleigh number, we show that a large-scale depth-invariant flow is formed, reminiscent of the condensate state observed in two-dimensional flows. We show that the large-scale circulation shares many similarities with the so-called vortex, or slow-mode, of forced rotating turbulence. Our investigations show that at a fixed rotation rate the large-scale vortex is only observed for a finite range of Rayleigh numbers, as the quasi-two-dimensional nature of the flow disappears at very high Rayleigh numbers. We observe slow vortex merging events and find a non-local inverse cascade of energy in addition to the regular direct cascade associated with fast small-scale turbulent motions. Finally, we show that cyclonic structures are dominant in the small-scale turbulent flow and this symmetry breaking persists in the large-scale vortex motion.

Item Type: Article
Additional Information: Copyright 2014 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Favier, B., L. J. Silvers, and M. R. E. Proctor. "Inverse cascade and symmetry breaking in rapidly rotating Boussinesq convection." Physics of Fluids (1994-present) 26.9 (2014): 096605. and may be found at http://dx.doi.org/10.1063/1.4895131
Subjects: T Technology > TA Engineering (General). Civil engineering (General)
Divisions: School of Engineering & Mathematical Sciences > Department of Mathematical Science
URI: http://openaccess.city.ac.uk/id/eprint/3988

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