  The compaction dynamics of a granular media subject to a sequence of vertical
taps made of fluid pulses is investigated via Molecular Dynamics simulations.
Our study focuses on three different levels: macroscopic (volume fraction),
mesoscopic (Vorono\"{\i} volumes, force distributions) and microscopic (grain
displacements). We show that the compaction process has many characteristics
which are reminiscent of the slow dynamics of glass forming systems, as
previously suggested. For instance the mean volume fraction slowly increases in
time and approaches a stationary value following a stretched exponential law,
and the associated compaction time diverges as the tapping intensity decreases.
The study of microscopic quantities also put in evidence the existence of
analogies with the dynamics of glass formers, as the existence of dynamical
heterogeneities and spatially correlated motion of grains; however it also
shows that there are important qualitative differences, as for instance in the
role of the cage effect. Correlations between geometry and dynamics of the
system at the grain level are put in evidence by comparing a particle
Vorono\"{\i} volume and its displacement in a single tap.
