[WIP] Fix enthalpy related issues

[bigfooted]

Proposed Changes

• use reference temperature for enthalpy consistenly
• Write temperature to paraview when energy=off, being consistent with other thermodynamic quantities like viscosity.
• Fixed a bug when restarting with species.
• When energy=off, enthalpy field will still be used to compute temperature (necessary for python wrapper)
• Fixed an MPI bug where viscosity was out of sync when computing non-constant mass diffusivity
• update python wrapper case. No need to put ENERGY=ON anymore. temperature field is written to paraview

Related Work

small fixes for #2426

PR Checklist

Put an X by all that apply. You can fill this out after submitting the PR. If you have any questions, don't hesitate to ask! We want to help. These are a guide for you to know what the reviewers will be looking for in your contribution.

• I am submitting my contribution to the develop branch.
• My contribution generates no new compiler warnings (try with --warnlevel=3 when using meson).
• My contribution is commented and consistent with SU2 style (https://su2code.github.io/docs_v7/Style-Guide/).
• I used the pre-commit hook to prevent dirty commits and used pre-commit run --all to format old commits.
• I have added a test case that demonstrates my contribution, if necessary.
• I have updated appropriate documentation (Tutorials, Docs Page, config_template.cpp), if necessary.

[bigfooted]

@Cristopher-Morales I added the standard reference temperature to the sensible enthalpy computation everywhere. Was there a reason that sometimes Tref=298.15 and sometimes you use Tref=0? I think it should always be 298.15, so I also removed the option from the config file.

[Cristopher-Morales]

@Cristopher-Morales I added the standard reference temperature to the sensible enthalpy computation everywhere. Was there a reason that sometimes Tref=298.15 and sometimes you use Tref=0? I think it should always be 298.15, so I also removed the option from the config file.

Hi!

It was added like that because it was a comment suggested by Pedro, he said that hardcoding values was not a good practice. That one should be a user defined option. Also, the enthalpy for the other models is just h=cp*T, that is the enthalpy used by a perfect gas, it is also mention in the book of blazek. I just kept the default behaviour of the other models as they were defined before.

[bigfooted]

The STD_REF_TEMP=298.15 is now in option_structure.hpp, I think this is the best place for it.

It is going to be very confusing when converting enthalpies with different definitions, so maybe better to keep it consistent across models and use the same constant everywhere.