Introduction of AUSM+M and AUSM scheme refactoring in NEMO

[fmpmorgado]

Proposed Changes

This PR makes several changes to the NEMO code:
1.) @fmpmorgado Introduced the AUSM+M convective scheme that avoids the carbuncle phenomena in hypersonic blunt bodies (https://doi.org/10.1016/j.apm.2019.09.005)
2.) Wally - A full refactoring of the AUSM schemes within NEMO
3.) Removal of AUSMPW+ scheme

Related Work

This work is a follow-up and a cleaner version of the work in the branch feature_NEMO_AUSMPLUSM. I will delete both branches after merge.

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 have added a test case that demonstrates my contribution, if necessary.
• I have updated appropriate documentation (Tutorials, Docs Page, config_template.cpp), if necessary.

Benchmark

I have conducted a comparison between the AUSM and AUSM+M for a 2D axisymmetric non-equilibrium flow over a cylinder with a 0.1 meter diameter and a freestream of M=24, P = 10.23 N and T = 224.5 K.

The left image represents the converged 2nd order solution using AUSM+M and the right image using the standard AUSM scheme. The new AUSM+M scheme enables to get rid of the pressure oscillations near the stagnation area.

Temperature at the stagnation line (solid line is AUSM+M and dashed line is AUSM)

Pressure at the stagnation line and close-up at the stagnation point (solid line is AUSM+M and dashed line is AUSM)

[pcarruscag]

Not for this PR, but the documentation update the NEMO team should consider is this one https://su2code.github.io/docs_v7/Convective-Schemes/, the config_template is not much use for users since it does not say what schemes can be used with what fluid models.

[lgtm-com]

This pull request introduces 2 alerts when merging 84cdb7e into d32ccec - view on LGTM.com

new alerts:

• 2 for Resource not released in destructor

[lgtm-com]

This pull request introduces 2 alerts when merging 787c7ea into bc6ef2a - view on LGTM.com

new alerts:

• 2 for Resource not released in destructor

[jtneedels]

Code LGTM, I think the refactoring makes sense. Thanks Wally!

[pcarruscag]

Nice work with the refactoring 👍
Run clang-format on the new files please.

[pcarruscag]

I ran clang-format (because we want to make a release this Monday) LGTM on my side we can move those functions another day.