[FLASH-USERS] cell density goes to zero when refining several times

[Andrea Gatto]

Dear all,

I'm running a simulation with FLASH 4.0.1 of a turbulent interstellar medium.

For different reasons, some regions of my domain are refined several times
during the evolution (nrefs=2), so that every two timesteps blocks in the
same region are refined, derefined, refined again etc.

After few hundreds timesteps, however, the code crashes due to a steep
increase in internal and kinetic energy.
Every time I checked, I found that a single/few cells belonging to one of
this highly time-varying blocks show a density that rapidly goes to zero
and a subsequent explosion in temperature and velocity.

I tried several solutions, such as the inclusion of guard cells filling
routines in different parts of the code, but the problem remains.

This doesn't happen when the blocks are not refined so often.

Do you have any idea on how to solve this problem?

Thank you.

Best,

Andrea