bendudson / hermes-3

Multifluid drift reduced fluid model
GNU General Public License v3.0
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Implement 2D neutral equation fixes originally part of AFN flux limiter branch #231

Open mikekryjak opened 5 months ago

mikekryjak commented 5 months ago

There is an outstanding PR which has fixes for neutral equations as well as the new limiter scheme. It lives on my fork at https://github.com/mikekryjak/hermes-3/pull/5.

The flux limiter scheme has caused us lots of inexplicable slowdowns, and we were waiting with the merge until we resolved that along with the X-point temperature spike bug. With those two problems having turned out to be challenging, I think we should fix the equations in a separate PR as they are simply not correct. We can then tackle the limiter scheme methodically bit by bit.

I had to merge the other 2D neutral fixes PR into this as both are required for the tests. That other PR is causing checkerboarding in the neutral_mixed integrated test.

To do:

Original work from @bendudson: image

Impact on results is not insubstantial, especially at the target. Performance is the same or slightly faster - probably dependent on the change in conditions rather than being more difficult numerically.

OMP image

Target image

Poloidal slice image