expand and eventually eliminate the multi-phase structure of the gas. In order to simulate this process in detailed, we adopt a 2-D numerical hydrodynamic scheme with a multi-phase medium.

The motion of clouds relative to, and their interaction with an external medium has been studied by numerous authors. [@MI94a] examined ram-pressure stripping due to the supersonic motion of gas past clouds confined within minihalos, a very different situation from that described above for the evolution of the WFC’s. Tenorio-Tagle et al. (1986, 1987) examined the interactions of clouds hitting relatively high density galactic disks at high speeds. Again, that is a very different situation from the evolution of the WFC’s, which move slowly through a low density medium with a smooth density distribution. [@MWBL93] examined the loss of gas from a cloud due to the growth of Kelvin-Helmholtz instability for transsonic motions. As with the above studies, however, the energy transfer between the cloud and the background gas was not examined.

We proceed by briefly describing our method and the model parameters in §2. In §3, we analyze the results of our computations. Finally we discuss the implication of these results in §4.

Numerical Method and Model Parameters
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Equation 