  The generation of turbulence at magnetized shocks and its subsequent
interaction with the latter is a key question of plasma- and high-energy
astrophysics. This paper presents two-dimensional magnetohydrodynamic
simulations of a fast shock front interacting with incoming upstream
perturbations, described as harmonic entropy or fast magnetosonic waves, both
in the relativistic and the sub-relativistic regimes. We discuss how the
disturbances are transmitted into downstream turbulence and we compare the
observed response for small amplitude waves to a recent linear calculation. In
particular, we demonstrate the existence of a resonant response of the
corrugation amplitude when the group velocity of the outgoing downstream fast
mode matches the velocity of the shock front. We also present simulations of
large amplitude waves to probe the non-linear regime.
