to $C_h=1$. The initial location of the WFC’s is set to be at $x_0=y_0=0$. The value of $g$ is uniform throughout the grid, justified by the fact that the computational domain represents a small fraction of a galaxy. For Models 1-3, we set $g=0.1$, so that $r_h = 10$, while in Model 4, $g=0.05$, giving $r_h = 20$. We set $\rho_0=1$. In these units, Equation (\[eq:den\]) reduces to $$\rho_h = {\rm e}^{-g\left(y - y_0\right)}.$$ The computational domain extends from -0.75 to 0.75 in $x$, and from -15 to 1 in $y$. At the base of the computational domain, $\rho_h
/\rho_0 \sim 4.5$ for Models 1-3, and 2.1 for Model 4.

Parameters for the Warm Fragmentary Clouds
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The density ratio at the launch point, $D_{\rho}\equiv \rho_w/\rho_h =10^{2}$ in Models 1-3, while $D_\rho = 25 $ in Model 4. The magnitude of $D_\rho$ would be constant throughout the simulation time if 1) the WFC’s retain their integrity, 2) $\gamma_h = \gamma_w$, and 3) there is no shock dissipation to modify $K_h$ and $K_w$. In general, however, $D_\rho$ is a function of $y$, depending on the equation of state for both the WFC’s and RHG.

The value $D_{\rho}=100$ is selected to represent 