REYNOLDS STRESSES AND DIFFERENTIAL ROTATION IN BOUSSINESQ CONVECTION IN A ROTATING SPHERICAL-SHELL

We consider the problem of how numerical simulations of convection in a spherical shell can be used to estimate turbulent transport coeffici ents that may be used in mean field theory. For this purpose we analys e data from simulations of three dimensional Boussinesq convection. Th e rotational influence on convection is described in terms of the LAMB DA-effect and anisotropic eddy conductivity. When the resulting transp ort coefficients are used in a mean field model, the original rotation law is recovered approximately. We thus conclude that the flow can be described in terms of a LAMBDA-effect. Our results are also compared with analytical theories and observations.