  The meridional circulation plays an essential role in determining the basic
mechanism of the dynamo action in case the of a low eddy diffusivity.
Flux-transport dynamos with strong return flow and a deep stagnation point are
discussed in the case of a positive $\alpha$-effect located in the overshoot
layer and a rotation law consistent with helioseismology. By means of a linear
dynamo model, it will be shown that the migration of the toroidal belts at
lower latitudes and the periods of the activity cycles are consistent with the
observations. Moreover, at variance with previous investigations, the typical
critical dynamo numbers of dipolar solutions are significantly smaller that
those of quadrupolar solutions even in the regime of strong flow.
