Compositional Convection in Planetary Interiors: Is There an "Ultimate" Regime?
Abstract
Compositional buoyancy is likely a dominant source of energy in the interiors of many planets. The distinction between thermal and compositional buoyancy is primarily due to the significantly lower mass diffusivity characterizing the latter. Because of this difference the flows in compositional convection remain coherent and quasi-laminar for large ranges in the buoyancy forcing, with inertia tending to play a subdominant role. While this suggests that the Reynolds number based on the scale of convection remains low as the buoyancy force increases, most planets are characterized by extremely large compositional Rayleigh numbers where turbulence is likely present. We investigate compositional convection in a rotating plane layer with realistic fluid properties and boundary conditions via numerical simulations of an asymptotically reduced equation set that is valid in the limit of small Rossby and small Ekman numbers. In particular, we determine at what Rayleigh numbers inertia becomes important in compositional convection, and whether an ``ultimate regime" might exist.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFMNG23A1486C
- Keywords:
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- 4490 NONLINEAR GEOPHYSICS Turbulence