evolution approaches the $t^{2/5}$ law found by WL. For this case an effective density, i.e. the density that the corresponding Sedov-Taylor expansion would require, is 0.455 cm$^{-3}$.\[fig:rs\_C\]](comp_rshock_vs_C3){width="49.00000%"}

For our calculations we do find that the shock evolution depends to some degree on the particular cloud realization used. This is illustrated in Figure \[fig:rs\_evol\] which shows the shock evolution for several different cloud realizations. For most of our runs we have used only half of the 2D volume, $z \geq 0$. The figure shows that the shock evolution for different runs using the 2D half volume differ though the variations are at about the 10% level. We have tested the effects of using the 2D half volume by doing a full volume run, shown as the red dash-dotted line in Figure \[fig:rs\_evol\]. We find no significant difference in that run as compared with other runs with the same $C$ value. We have also compared with a 3D runs (using one octant of the space) done in cartesian coordinates. Again, as demonstrated in Figure \[fig:rs\_evol\] we find no significant difference from the 2D half volume runs. Because of the computational and visualization demands of the 3D runs, they were done with only 