[Users] Using finite temperature EOS with GRHydro in BNS simulation

[Roland Haas]

Hello Beyhan,

>    I am using Turing release on Fedora 31. I have been trying to
>    perform a binary neutron star merger simulation via finite
>    temperature equation of state (might be misleading) with GRHydro. As
>    far as I can see, this question was replied by Roland previously in
> http://lists.einsteintoolkit.org/pipermail/users/2019-February/006756.html.
> 
> Parameters were added as has been suggested but If Meudon_BNS_ID does
> not refer to source code of Meudon_Bin_NS then I could not find where
> Meudon_BNS_ID or Meudon_Bin_NS ID is located in Cactus, if it does I
> will try to work on it.
Meudon_BNS_ID refers to the binary neutron star ID reader for LORENE
that is found in the toolkit. Indeed the correct name is Meudon_Bin_NS .

> In this setting, is it enough to use IOUtil parameter
> -filereader_ID_vars = "all" - to allow initial temperature, entropy and
> electron fraction to be read from the file?
Not quite. filereader reads in data from Cactus 3d output files.
However that is not what is done with the Meudon thorns. Instead they
are regular initial data thorns that read in data from LORENE's output
files. 

Looking at the file Meudon_Bin_NS/src/Bin_NS.cc then it will set
HydroBase::temperature and HydroBase::Y_e if those variables have
storage eg if you add

HydroBase::initial_temperature = "read from file"
HydroBase::initial_Y_e = "read from file"

Really though the Meudon thorn should extend the valid ranges of those
keywords to include "Meudon_Bin_NS" the way tit does for the other
initial_XXX parameters.

I noticed that there is a TOVSolverHot thorn in
http://svn.einsteintoolkit.org/incoming/TOVSolverHot/ that lets you
construct initial data for an isothermal TOV star and that may be a an
easier test before going for a full binary simulation.

> I have tried to use APR eos with SFH0 eos table from
> stellarcollapse.org (
> https://stellarcollapse.org/~evanoc/Hempel_SFHoEOS_rho222_temp180_ye60_version_1.1_20120817.h5.bz2
> ) and got "EOS errori n prim2con_hot"  in this setting and do not know
> how this might be overcomed.
There is not usually a really good general solution for this. It boils
down to gut feeling and experience with this particular type of
simulations. I would give the isothermal single TOV a try first and
once that works work my way up to a binary.

> Besides that, I suppose WhiskyTHC allows nuclear eos table to be used
> with Lorene initial data by providing this table in pizza format and
> uses some conversion of units but do not know what will be needed for
> Einstein Toolkit.
WhiskyTHC has a full example on how to use it in its tarball
http://personal.psu.edu/dur566/downloads/WhiskyTHC.tar. Its output is
in the regular ET HydroBase variables so not really different from when
using GRHydro.

Yours,
Roland

-- 
My email is as private as my paper mail. I therefore support encrypting
and signing email messages. Get my PGP key from http://pgp.mit.edu .
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 833 bytes
Desc: OpenPGP digital signature
Url : http://lists.einsteintoolkit.org/pipermail/users/attachments/20200621/564fabd2/attachment.bin