  We present a study of the turbulent velocity fields in the Intra Cluster
Medium of a sample of 21 galaxy clusters simulated by the SPH--code Gadget2,
using a new numerical scheme where the artificial viscosity is suppressed
outside shocks. The turbulent motions in the ICM of our simulated clusters are
detected with a novel method devised to better disentangle laminar bulk motions
from chaotic ones. We focus on the scaling law between the turbulent energy
content of the gas particles and the total mass, and find that the energy in
the form of turbulence scales approximatively with the thermal energy of
clusters. We follow the evolution with time of the scaling laws and discuss the
physical origin of the observed trends. The simulated data are in agreement
with independent semi--analytical calculations, and the combination between the
two methods allows to constrain the scaling law over more than two decades in
cluster mass.
