  We present models the gas physics and dynamics of the inner 50 pc of the
Galaxy. In a first step the gas properties of an isolated clumpy circumnuclear
disk were analytically investigated. We took the external UV radiation field,
the gravitational potential, and the observed gas temperature into account. The
model includes a description of the properties of individual gas clumps on
small scales, and a treatment of the circumnuclear disk as a quasi-continuous
accretion disk on large scales. In a second step the dynamics of an isolated
circumnuclear disk were investigated with the help of a collisional N-body
code. The environment of the disk is taken into account in a third step, where
we calculated a pro- and a retrograde encounter of an infalling gas cloud with
a pre-existing circumnuclear disk. In order to constrain the dynamical model,
we used the NIR absorption of the giant molecular clouds located within the
inner 50 pc of the Galaxy to reconstruct their line-of-sight distribution.
