The model

Our methodology is to try and understand the influence of turbulent dynamics on transport properties of convection. In order to be able to do this, we extract only the most important of the many effects operating in stars like the Sun i.e. we include the compressibility of the gas and impose an underlying density stratification, but we ignore magnetic fields, ionisation, variable opacities, radiative boundary condtions etc etc. Earlier work (Cattaneo et al. 1991 Astrophys. Jou., 370, 282) showed that transition from laminar to turbulent dynamics in the simulations altered the energy transport properties considerably. The latest simulations, presented here, include rotation in the hope that similar differences occur between the laminar and turbulent transport of momentum. Why do we hope this? Well, previous numerical simulations and observational (helioseismology) results for the solar differential rotation, created by angular momentum transport, disagree and we think that the lack of turbulent dynamics in the previous computations may account for this.

Our effort is then directed at the turbulent regime. In order to be able to resolve such solutions with their wide range of scales, we can simulate only a portion of the full spherical-shell convection zone.

• The authors. The real stars!

• The geometry. We use a local-area model extracted from the global situation in order to be able to resolve the turbulent scales.

• The model. The model is a local-area, cartesian domain containing ideal gas subjected to f-plane rotation and thermal forcing from below.

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