we find more stable values for K, which still fall roughly in the predicted range.

Cloud Evaporation Rate
----------------------

Within the WL model the value of $\tau$, the ratio of evaporation timescale to remnant age, is treated as a free parameter. In our numerical work, this is not the case, since given the initial conditions the cloud evaporation timescale will follow from the physics, including the temperature of the surrounding hot gas and the complex heat flow patterns that develop as the clouds are both evaporated and disrupted by shear flows. In addition, clouds close to the explosion center can be heated enough by being shocked that they could be considered part of the hot gas, though still overdense. However, as we discuss below, such clouds are overpressured compared to the surrounding medium and so they expand and cool at later times in the remnant evolution.

Clouds that are farther from the center do not get heated to high temperatures by the expanding shock but are subject to shear flows and thermal conduction. However, even for these clouds, characterizing the evaporation rate is not entirely straightforward since gas exists at a range of temperatures and densities within the remnant at 