[FLASH-USERS] Planetary impact with moving solid projectile

[Ryan Farber]

Hi Andrea,

That's an interesting problem you'd like to simulate! Regarding the error
you're receiving, I usually see that happens when the timestep (dt) drops
below 1e-10. In my case, usually a velocity gets too large. However, in
your case it's interesting the error occurs immediately after mesh
refinement (so possibly dx becomes quite small which also influences the
CFL constraint).

Does that error occur even if you turn off AMR? (That is, set lrefine_min =
lrefine_max = constant OR set nrefs = large).

Back to what you're trying to simulate, I'd think you'd want to use
BDRY_VAR to simulate solids in FLASH. However, in that case you're not
actually simulating the evolution of the internal structure of the solid
material (instead, it applies boundary conditions).

Anyway, I think FLASH might be suitable for your problem since it sounds
somewhat analogous to Mullen & Gammie 2020's work on the giant impact
formation of the Moon, which uses Athena++ (and FLASH is a similar code).

Good luck!
--------
Ryan


On Mon, Apr 12, 2021 at 2:30 PM Andrea Zorzi <zorzi at stanford.edu> wrote:

> Dear Klaus,
>
> Thank you for your email. You are right, this is my mistake. Nonetheless,
> even setting:
>
>  sim_pAtm                = 1.
>  sim_pTarg               = 1.
>
> throws me the same error as described, even when more realistic values,
> e.g. sim_pAtm=101325 Pa and sim_pTarg=10^7 Pa, are input. If helpful, the
> new dat, log files and the command line output are attached.
>
> Andrea
>
>
>
>
>
> > Il giorno 12 apr 2021, alle ore 11:11, Klaus Weide <
> klaus at flash.uchicago.edu> ha scritto:
> >
> > Andrea,
> >
> > Without trying to answer your questions substantially, I would just like
> > to point out that you have, in your flash.par,
> >
> >  sim_pAtm             = 0.
> >  sim_pTarg            = 0.
> >
> > so it seems you are initializing various pressures to 0.
> > That shouldn't really work, and I am a bit surprised your simulation got
> > even as far as it did.
> >
> > Klaus
>
>
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