  Meridional flow results from slight deviations from the thermal wind balance.
The deviations are relatively large in the boundary layers near the top and
bottom of the convection zone. Accordingly, the meridional flow attains its
largest velocities at the boundaries and decreases inside the convection zone.
The thickness of the boundary layers, where meridional flow is concentrated,
decreases with rotation rate, so that an advection-dominated regime of dynamos
is not probable in rapidly rotating stars. Angular momentum transport by
convection and by the meridional flow produce differential rotation. The
convective fluxes of angular momentum point radially inward in the case of slow
rotation but change their direction to equatorward and parallel to the rotation
axis as the rotation rate increases. The differential rotation of main-sequence
dwarfs is predicted to vary mildly with rotation rate but increase strongly
with stellar surface temperature. The significance of differential rotation for
dynamos has the opposite tendency to increase with spectral type.
