Abstract
Motivated by the recent discovery of subsurface oceans on planetary moons and the interest they have generated, we explore convective flows in shallow spherical shells of dimensionless gap width in the rapid rotation limit , where is the Ekman number. We employ direct numerical simulation (DNS) of the Boussinesq equations to compute the local heat flux as a function of the latitude and use the results to characterize the trapping of convection at low latitudes, around the equator. We show that these results are quantitatively reproduced by an asymptotically exact nonhydrostatic equatorial -plane convection model at a much more modest computational cost than DNS. We identify the trapping parameter as the key parameter that controls the vigor and latitudinal extent of convection for moderate thermal forcing when and . This model provides a theoretical paradigm for nonlinear investigations.
3 More- Received 22 September 2017
DOI:https://doi.org/10.1103/PhysRevFluids.3.053801
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