advecting_white_dwarf setup sees substantial heating

[maximumcats]

This setup resembles the sort of advection across the grid seen in wdmerger. When running at the problem's default (low) resolution, the star heats to a maximum temperature of over 1e9 K despite there not being any heat source on the domain. This causes a problem for simulations with reactions because it can cause the star to spontaneously ignite.

[maximumcats]

The heating primarily happens near the (trailing) edge of the star. So it may be that a disproportionate amount of kinetic energy is being transferred to the lower density zones, relative to their densities.

Also I observe that this is not dependent on timestep size, even with CFL = 0.01 the effect is robust.

[zingale]

it surely depends on resolution though, right?

[zingale]

there seem to be a lot of CFL violations and retries

[maximumcats]

it surely depends on resolution though, right?

It does. At resolutions of 100 km, 50 km, and 25 km, the peak temperatures during the run are 6.2e8 K, 3.4e8 K, and 1.9e8 K, respectively.