[FLASH-USERS] [EXT] Re: Computed hydro dt is not positive

Acharya, Nitish nachary2 at ur.rochester.edu
Tue Sep 22 17:09:35 EDT 2020


Hi Klaus,

Thank you for your suggestions.

I checked my EOS file which I have attached here. The data (species #2) looks just fine but I am still getting the same error right during driver initialization. I have tried reducing the time step and tried to tune couple more runtime params but the error persists. It's just hard to know at this point what's causing this error.

I would really appreciate your help,

Thanks,
Nitish
________________________________
From: flash-users-bounces at flash.uchicago.edu <flash-users-bounces at flash.uchicago.edu> on behalf of Klaus Weide <klaus at flash.uchicago.edu>
Sent: Thursday, September 17, 2020 2:34 PM
To: flash-users at flash.uchicago.edu <flash-users at flash.uchicago.edu>
Subject: [EXT] Re: [FLASH-USERS] Computed hydro dt is not positive

On Thu, 17 Sep 2020, Acharya, Nitish wrote:

> I have been applying the analytical ideal gas EOS to simulate my
> material for a LaserSlab based problem. Recently, instead of using an
> equation, I used the same ideal gas model and built a tabulated IONMIX
> EOS. However, as I use the tabulated EOS for the simulation, I've been
> repeatedly getting an error during driver initialization

FLASH should generate a file EOS_printout_tables.txt when it starts up.
The first thing I would do is carefully check that file:

*  Do all the data make sense?
*  Are all values positive that physically should be positive
   (energies, pressures)?
*  Are all pressures and energies monotonically increasing with increasing
   temperature?
*  You should have a nonzero Z(T,density) function (shown under the
   heading IONIZATION DATA in the printout file); it should be constant
   if your EOS table file is meant to exactly represent a (3T) Gamma Eos.

Klaus
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