the resolution, the models are run in two dimensions. Because Cosmos runs on a Cartesian grid, this means that the clouds simulated are actually slices through infinite cylinders, rather than spheres. This limitation should not, however, significantly alter our conclusions, and allows us to run the simulations at significantly higher resolution than would be possible in three dimensions. The resolutions of the models are 300x3200 zones. The clouds are therefore resolved by 80 zones across their diameters. This is somewhat poorer than the resolution found necessary by Klein, McKee, & Colella (1994) for their study of shock-cloud interactions. Because the clouds in our models are not subject to extreme shocks, however, lower resolutions should be adequate, and reductions in resolution by a factor of two have not been found to have any affect upon our results.

Because we are concerned with energy transfer and dissipation, the form of the artificial viscosity used in the models might be expected to play a significant role. In order to examine that possibility, we have computed versions of Model 1 using both scalar and tensor forms of the artificial viscosity, with the coefficient varied by a factor of two, and both with and without 