  We present results from consistent dynamo simulations, where the electrically
conducting and incompressible flow inside a cylinder vessel is forced by moving
impellers numerically implemented by a penalization method. The numerical
scheme models jumps of magnetic permeability for the solid impellers,
resembling various configurations tested experimentally in the von-Karman
Sodium experiment. The most striking experimental observations are reproduced
in our set of simulations. In particular, we report on the existence of an
axisymmetric dynamo mode, self-consistently generated when the magnetic
permeability of the impellers exceeds a threshold. We describe a possible
scenario involving both the turbulent flow in the vicinity of the impellers and
the high magnetic permeability of the impellers.
