Decoupling between the ``background mesh`` and ``front mesh`` if there is no hole present [overset] (#1408) · Issues · Development / OpenFOAM-plus

Decoupling between the ``background mesh`` and ``front mesh`` if there is no hole present [overset]

Summary

I'm sorry for reporting again about overset but it happens that I'm running few tests nowadays. The algorithm doesn't set any interpolated cells on the background mesh when there is no holes in the model. This leads to complete decoupling between the background mesh and front mesh.

Steps to reproduce

Since there is not geometry needed, simple empty overlapping meshes of any type or shape can reproduce this issue. In order to see the issue clearly, I would suggest selecting actuation disk on the front mesh or the front and back together. By inspecting the case in paraview, you will not found any interpolated cells on the background mesh. Also, both velocity and pressure fields on the background mesh are disturbed by the disk (of course in case, the disk is selected from the front mesh cells only). Using overSimpleFoam is enough to see this behavior.

Example case

Environment information

OpenFOAM version : v1906, commit 506990e0
Operating system : Ubuntu 18.04LTS
Hardware info :
Compiler : gcc

Possible fixes

If this feature is not supported, maybe just through a warning or fatal error would be enough for the user to understand the limitation of the method. A solution for this issue could be by selecting few layers inwards around the oversetPatch to ensure the coupling. Or just marking few cells in the background as a hole before adding the interpolation layers. Probably, it is more trick than that specially if the front mesh is moving.

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### Summary

I'm sorry for reporting again about ``overset`` but it happens that I'm running few tests nowadays.
The algorithm doesn't set any ``interpolated`` cells on the background mesh when there is no ``holes`` in the model.
This leads to complete decoupling between the ``background mesh`` and ``front mesh``.

### Steps to reproduce

Since there is not geometry needed, simple empty overlapping meshes of any type or shape can reproduce this issue.
In order to see the issue clearly, I would suggest selecting actuation disk on the ``front mesh`` or the front and back together.
By inspecting the case in ``paraview``, you will not found any interpolated cells on the background mesh. Also, both velocity and pressure fields on the background mesh are disturbed by the disk (of course in case, the disk is selected from the front mesh cells only). Using ``overSimpleFoam`` is enough to see this behavior.

### Example case

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![wakeInside](/uploads/0322e6124579bf0f5ed67ab6edc737ba/wakeInside.png)

### Environment information

- OpenFOAM version : v1906, commit 506990e079af
- Operating system : Ubuntu 18.04LTS
- Hardware info    :
- Compiler         : gcc

### Possible fixes

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  problem

The "/label ~bug" text is a gitlab flag that will add the "bug" label to this
  issue
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If this feature is not supported, maybe just through a warning or fatal error would be enough for the user to understand the limitation of the method.
A solution for this issue could be by selecting few layers inwards around the ``oversetPatch`` to ensure the coupling. Or just marking few cells in the background as a hole before adding the interpolation layers. Probably, it is more trick than that specially if the front mesh is moving.