  We present the results of three-dimensional simulations of the deep
convective envelope of a young (10 Myr) one-solar-mass star, obtained with the
Anelastic Spherical Harmonic code. Since young stars are known to be faster
rotators than their main sequence counterparts, we have systematically studied
the impact of the stellar rotation speed, by considering stars spinning up to
five times as fast as the Sun. The aim of these nonlinear models is to
understand the complex interactions between convection and rotation. We discuss
the influence of the turbulence level and of the rotation rate on the intensity
and the topology of the mean flows. For all of the computed models, we find a
solar-type superficial differential rotation, with an equatorial acceleration,
and meridional circulation that exhibits a multicellular structure. Even if the
differential rotation contrast decreases only marginally for high rotation
rates, the meridional circulation intensity clearly weakens according to our
simulations. We have also shown that, for Taylor numbers above a certain
threshold (Ta>10^9), the convection can develop a vacillating behavior. Since
simulations with high turbulence levels and rotation rates exhibit strongly
cylindrical internal rotation profiles, we have considered the influence of
baroclinic effects at the base of the convective envelope of these young Suns,
to see whether such effect can modify the otherwise near cylindrical profiles
to produce more conical, solar-like profiles.
