Differential Rotation in Stars with Convective Envelopes.

The rotation of a viscous shell is investigated in which the viscosity is caused by convection and is not isotropic. With a plausible assumption for the viscosity tensor, the problem can be solved with an approximation method that is valid for sufficiently high viscosity (or sufficiently slow rotation). The solution shows meridional circulation and differential rotation in the shell. Numerical solutions for constant density p and constant viscosity in the shell are found and compared with the motions in the hydrogen convective zone of the sun.