3-DIMENSIONAL CALCULATIONS OF THE EVOLUTION OF SUPERBUBBLES IN A CLOUDY MEDIUM

We, present three-dimensional numerical calculations of superbubbles e volving in a two-component interstellar medium composed of small diffu se clouds and a low-density intercloud medium. Cold H I clouds with in ternal densities n similar to 10 cm(-3) and radii R(cl) = 3-5 pc were assumed to be embedded in a warm plane-stratified intercloud medium. T he fraction of the total gas mass in clouds ranges between 0 and 0.5, whereas the cloud volume filling factor does not exceed 10%. The calcu lations determine the role played by dynamic disruption of clouds and by thermal evaporation from both the cold shell and the cloudy medium. It is found that mass loading from either disrupted or evaporated clo uds dominates the mass input rate into the cavity, and the mass evapor ated from the shell is important only at early times. The effects of d ifferential galactic rotation, the gravitational field of the disk, an d the location of the OB associations in the Galaxy are included also. The main properties of the giant remnants (energetics, morphology, to tal and X-ray luminosity, etc.) are estimated.