  We address the question of the dynamics in the inner 50 pc of the Galactic
Centre. In a first step we investigate the cloud-cloud collision rate in the
Circumnuclear Disk (CND) with the help of a three dimensional N-body code using
gas particles that can have inelastic collisions. The CND might be a longer
lived structure than previously assumed. The whole disk-like structure of the
CND can thus survive for several million years. A realistic simulation of the
CND shows the observed disk height structure. In a second step the environment
of the CND is taken into account. Retrograde and prograde encounters of a cloud
of several 10^4 M_solar falling onto an already existing nuclear disk using
different energy loss rates per collision are simulated. The influence of the
energy loss rate per collision on the evolution of the mass accretion and cloud
collision rates is strongest for a prograde encounter. A composite data cube of
two different snapshots of a prograde encounter together with the CND shows
striking similarity with the observed Sgr A cloud complex. The current
appearance of the Galactic Centre environment can thus be explained by at least
two dynamically distinct features together with the CND. The current mass
accretion rate within the CND ranges between 10^-3 and 10^-4 M_solar yr^-1. It
can rise up to several 10^-2 M_solar yr^-1 during massive accretion events.
