[FLASH-USERS] overwriting default density floor on FLASH

[Jung Lin Doris Lee]

Flash community,

We have a (hopefully simple) question about how to best change the
numerical floors for state quantities like density and pressure. For
context, we are trying to reproduce the cloud collapse problem of Foster &
Chevalier (ADS <http://adsabs.harvard.edu/abs/1993ApJ...416..303F>), which
require densities of 10^-19~10^-27g/cm^3. The setup has a spherical core in
the central ~1/2 of the domain with a radial profile in density. Outside
the sphere is a tenuous and hotter medium (a reduced density but increased
temperature so that it remains in pressure balance with the edge of the
sphere).

For example, when we initialize the data, we receive the following warning:

WARNING after gc filling: min. unk(DENS_VAR)=0.7259099999999999388370E-20
PE=0 block=10 type=1

And the initial outputs show that the density has become entirely uniform
after which the program crashes because of non-convergence in the Riemann
subroutine. Grep-ing around, we see that there are quantities like “smallp”
or “smlrho”, whose default values are 10^-10g/cm^3, indeed larger than the
values we are initializing. We tried setting a value for smlrho in
flash.par, but it did not appear to do anything.

Can these values be reset in flash.par versus going into the source code?
We are glancing through the user guide and example problems and can not
find an example of how to do this.

Best,

Doris and Aaron
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