  The evolution of galactic disks from their early stages is dominated by
gasdynamical effects such as gas infall, galactic fountains, and galactic
outflows, and further more. The influence of these processes is only
understandable in the framework of diverse gas phases differing in their
thermal energies, dynamics, and element abundances. To trace the temporal and
chemical evolution of galactic disks, it is therefore essential to model the
interstellar gasdynamics combined with stellar dynamics, the interactions
between gas phases, and star-gas mass and energy exchanges as detailed as
possible. This article reviews the potential of state-of-the-art numerical
schemes like Smooth-Particle and grid-based hydrodynamics as well as the
inherent processes as of star-formation criteria and feedback, energy deposit
and metal enrichment by stars and on the influence of gas-phase interactions on
the galactic gas dynamics and chemistry.
