Double-diffusive convection in a rotating cylindrical annulus with conical caps

Simitev, R.D. (2011) Double-diffusive convection in a rotating cylindrical annulus with conical caps. Physics of the Earth and Planetary Interiors, 186(3-4), pp. 183-190. (doi:10.1016/j.pepi.2011.04.007)

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Publisher's URL: http://dx.doi.org/10.1016/j.pepi.2011.04.007

Abstract

Double-diffusive convection driven by both thermal and compositional buoyancy in a rotating cylindrical annulus with conical caps is considered with the aim to establish whether a small fraction of compositional buoyancy added to the thermal buoyancy (or vice versa) can significantly reduce the critical Rayleigh number and amplify convection in planetary cores. It is shown that the neutral surface describing the onset of convection in the double-buoyancy case is essentially different from that of the well-studied purely thermal case, and does indeed allow the possibility of low-Rayleigh number convection. In particular, isolated islands of instability are formed by an additional “double-diffusive” eigenmode in certain regions of the parameter space. However, the amplitude of such low-Rayleigh number convection is relatively weak. At similar flow amplitudes purely compositional and double-diffusive cases are characterized by a stronger time dependence compared to purely thermal cases, and by a prograde mean zonal flow near the inner cylindrical surface. Implications of the results for planetary core convection are briefly discussed.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Simitev, Dr Radostin
Authors: Simitev, R.D.
Subjects:Q Science > QA Mathematics
Q Science > QC Physics
College/School:College of Science and Engineering > School of Mathematics and Statistics > Mathematics
Journal Name:Physics of the Earth and Planetary Interiors
Journal Abbr.:Phys. Earth Planet. In
ISSN:0031-9201
Published Online:01 January 2011
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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
567421Geodynamo models driven by thermo-compositional convectionRadostin SimitevRoyal Society (ROYSOC)A Paramasivam 0Mathematics