  Recently, high resolution observations with the help of the near-infrared
adaptive optics integral field spectrograph SINFONI at the VLT proved the
existence of massive and young nuclear star clusters in the centres of a sample
of Seyfert galaxies. With the help of high resolution hydrodynamical
simulations with the PLUTO-code, we follow the evolution of such clusters,
especially focusing on mass and energy feedback from young stars. This leads to
a filamentary inflow of gas on large scales (tens of parsec), whereas a
turbulent and very dense disc builds up on the parsec scale. Here, we
concentrate on the long-term evolution of the nuclear disc in NGC 1068 with the
help of an effective viscous disc model, using the mass input from the large
scale simulations and accounting for star formation in the disc. This two-stage
modelling enables us to connect the tens of parsec scale region (observable
with SINFONI) with the parsec scale environment (MIDI observations). At the
current age of the nuclear star cluster, our simulations predict disc sizes of
the order of 0.8 to 0.9 pc, gas masses of 1.0e6 Msun and mass transfer rates
through the inner boundary of 0.025 Msun/yr in good agreement with values
derived from observations.
