  The effect of precession in a rotating sphere filled with fluid was studied
with direct numerical simulations, both in the incompressible hydrodynamics
(HD) and magnetohydrodynamics (MHD) scenarios. In both cases the asymptotic
state and its dependence with both rotating and precession frequency was
analyzed. For the MHD case no self-sustaining dynamos were found for the
prograde precession case, whereas on the other hand a critical retrograde
precession frequency was found above which dynamo action is self-sustained. It
was also found that these correspond to small-scale dynamos with a developed
turbulent regime. Furthermore, it is observed the presence of reversals of the
magnetic dipole moment with greater waiting times between reversals for smaller
precession frequencies.
