  We present a numerical scheme for modelling unresolved turbulence in
cosmological adaptive mesh refinement codes. As a first application, we study
the evolution of turbulence in the intra-cluster medium and in the core of a
galaxy cluster. Simulations with and without subgrid scale model are compared
in detail. Since the flow in the ICM is subsonic, the global turbulent energy
contribution at the unresolved length scales is smaller than 1% of the internal
energy. We find that the production of turbulence is closely correlated with
merger events occurring in the cluster environment, and its dissipation locally
affects the cluster energy budget. Because of this additional source of
dissipation, the core temperature is larger and the density is smaller in the
presence of subgrid scale turbulence than in the standard adiabatic run,
resulting in a higher entropy core value.
