[FLASH-USERS] Question about Simulation_AdjustEvolution

[Ryan Farber]

Hi Raymond,

Unless you've modified the equation of state (EOS; which you should
probably look into for simulating a non-ideal gas like water), it's
assuming you have an ideal gas. Likely, the update mode is DENS_EI so the
pressure, temperature are computed based on the density and internal energy
density (although there are the other sensible permutations as options as
well).

That's why modifying density affects the simulation and modifying
temperature doesn't.

So, you can change the EOS update mode (I think there's a runtime parameter
for that; you can find it in your logfile) or you can just make sure you
update all thermodynamic variables in Simulation_adjustEvolution (probably
the better option).

Best,
--------
Ryan


On Fri, Nov 6, 2020 at 6:17 PM Raymond B Li <raymondl at mit.edu> wrote:

> Hi,
>
> I'm using FLASH to simulate shock waves through water. I would like to
> change the temperature of a certain region of water to simulate a very
> short laser to generate shock waves.
>
> I've been trying to use Simulation_adjustEvolution to change the
> temperature of the material in a certain region while the simulation is
> running. However, I'm not able to do so and I don't really know what the
> problem is.
>
> I have attached a folder that contains the simulation code. In the file
> Simulation_adjustEvolution, on line 77, I am trying to change the
> temperature variable to a new value. Unfortunately, what happens is that
> the simulation does not change at all. Even more strangely, when I change
> TEMP_VAR to DENS_VAR, the simulation does change to the expected result. I
> have also tried using PRES_VAR, but PRES_VAR does not work. Do you know
> what could be causing this behavior? Also, is there a better way to change
> the value of a certain variable in a certain region?
>
> I also tried changing the eosMode of the simulation in the example.par
> file (line 62) to "dens_temp", but that didn't seem to do anything either.
>
> Thanks for your help.
>
> Best,
> Raymond​​
>
> ​
>
>
>
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