Tracer with Sharp IB

[oguevremont]

Description

• Previously, the tracer physics used with the Sharp IB solver could not consider material dependent physical properties: both fluid and solid had the same diffusivity.
• Now, physical properties of immersed solids are defined using the solid 0 section, though only one solid can be used at the moment.
• A tracer diffusivity model based on the signed distance function used in the Sharp IB has been added, which allows to smooth the diffusivity transition at the fluid/solid interface. The architecture is there for future models and could serve as a base for reactive physics models used in heterogeneous catalysis.

Testing

• [tests/core/immersed_solid_diffusivity_tanh] Unit test for the tanh diffusivity transition model.
• [applications_tests/lethe-fluid-sharp/tracer_around_sphere] 2D application test where the tracer physics is used with the Sharp IB solver. This also tests the new diffusivity model.

Documentation

[doc/source/parameters/cfd/physical_properties] The new model has been added in new section where immersed solids models will be added in the future.

Miscellaneous (will be removed when merged)

This PR was done with more generality than needed in preparation of the reactive physics that will be implemented soon.

Checklist (will be removed when merged)

See this page for more information about the pull request process.

Code related list:

• [x] All in-code documentation related to this PR is up to date (Doxygen format)
• [x] Lethe documentation is up to date
• [x] New feature has unit test(s) (preferred) or application test(s), and restart files are in the generator folder
• [x] The branch is rebased onto master
• [x] Changelog (CHANGELOG.md) is up to date
• [x] Code is indented with indent-all and .prm files (examples and tests) with prm-indent

Pull request related list:

• [x] Labels are applied
• [ ] There are at least 2 reviewers (or 1 if small feature) excluding the responsible for the merge
• [x] If this PR closes an issue or is related to a project, it is linked in the "Projects" or "Development" section
• [x] If the fix is temporary, an issue is opened
• [ ] The PR description is cleaned and ready for merge

[blaisb]

@oguevremont is this ready to review or not ? It seems to be in an intermediary state. If so please remove the ready to review label

[oguevremont]

@oguevremont is this ready to review or not ? It seems to be in an intermediary state. If so please remove the ready to review label

It is not ready yet, I forgot to remove the ready to review label.

[blaisb]

@oguevremont do you have additional things to add or this is ready to merge? If this is ready to merge I'll let you add the label Reviewed and ready to merge and then I'll merge