[WIP] Implementation of eN transition model

[RichRoos]

Hello!

Proposed Changes

To continue current work being done on different transition models, I am working at the implementation of the eN model for low-turbulence external aerodynamics as proposed by James G. Goder and Mark D. Maughmer (10.2514/1.J052905). This model incorporates a new transport equation to describe the growth of the maximum Tollmien-Schlichting instability amplitude in the presence of a boundary layer.

Related Work

This work will be set-up in the same way as the LM model is in https://github.com/su2code/SU2/pull/1751 (which was also generally speaking how I had set up my own LM transition implementation) to make sure merging in a later stage will be easier.

Roadmap

I am hoping to achieve a working implementation of the eN transition method. This work will be done as finishing part of my master thesis. We will have to see if I have time to completely finish the V&V phase due to time restrictions. I have already done quite some work on implementing and verifying the LM method on a private branch and results show mixed results, especially at higher Re numbers (mentioned also by Menter et all.). Thus the step is made to see how these LM results will compare to eN results.

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.

[lgtm-com[bot]]

This pull request introduces 1 alert when merging 56b93c17431798f2bf55ce44caf895fb58549949 into 2642f7ff03e1d3a7571df7a9f4d2df1897e2bbba - view on LGTM.com

new alerts:

• 1 for Comparison result is always the same

[lgtm-com[bot]]

This pull request introduces 1 alert when merging fd515930d0aba9dcce488c5c8e30347a8e2a8722 into 2642f7ff03e1d3a7571df7a9f4d2df1897e2bbba - view on LGTM.com

new alerts:

• 1 for Comparison result is always the same

[pcarruscag]

Don't add meshes to the code repo, we have TestCases for that.

[lgtm-com[bot]]

This pull request introduces 1 alert when merging 604aadb251f637fad1385753cc06755652614ee2 into 2642f7ff03e1d3a7571df7a9f4d2df1897e2bbba - view on LGTM.com

new alerts:

• 1 for Comparison result is always the same

[sun5k]

Hi @RichRoos. Hi. I was looking forward to implementing your e^N model. Relatively recently, I read #1820. Can you share the problem you are facing?

[RichRoos]

Hey @sun5k

I think that discussion sums it up quite well. I had some trouble with high n values at the start of the simulation, as small n values still resulted in a small production addition, and thus increased the n values again. But I think I am able to control it. I will update the code today and work on some validation cases.