  We present N-body simulations of globular clusters, in orbits around the
Galaxy, in order to study quantitatively and geometrically the tidal effects
they encounter. The clusters are modelised with multi-mass King-Michie models
(Michie 1963), including mass segregation at initial conditions. The Galaxy is
modelled as realistic as possible, with three components: bulge, disk and dark
halo. The main finding is that there exist two giant tidal tails around the
globuler cluster in permanence along its orbit, whatever this orbit. The length
of these tails is of the order of 5 tidal radii, or greater. The escaped stars
are distributed radially as a power law in density, with a slope of -4. The
tails present substructures, or clumps, that are the relics of the strongest
shocks. Due to the compressive disk-shocking, the clusters display a prolate
shape which major axis is precessing around the z axis. The tails are
preferentially formed by the lowest mass stars, as expected, so that the tidal
truncation increases mass segregation. Internal rotation of the cluster
increases the mass loss. The flattening of dark matter cannot influence
significantly the dynamics of the clusters. The orientation and the strength of
the tidal tails are signatures of the last disk crossing, so that observed
tidal tails can constrain strongly the cluster orbit and the galactic model
(vertical scale of the disc).
