BreakMeshByBlockGenerator: how to split inner node among subdomains?

[favinom]

Hi all,

I am trying to use BreakMeshByBlockGenerator.
I have four blocks which are included in the domain. See picture.
If I call the BreakMeshByBlockGenerator the mid node is not split, which I understand from how it implemented.
Is there a way to also split that node?

Thank you

[GiudGiud]

hello

yes you can join up two domains at the top or bottom, then split. (using a RenameBlockGenerator before the BreakMeshBYBlock)
Then split that domain again (using a ParsedSubdomainGenerator for example)

[GiudGiud]

We can do DG with a contiguous mesh, and without duplicating the nodes. The nodal values can be different on each element

[favinom]

I would need the same structure of DG but just along some interfaces. I would need the interface integrals over \gamma in the formula at the beginning of page 19 of https://arxiv.org/pdf/2412.00443 .

Actually breaking the mesh and using interface kernels was a perfect combination.

How would you suggest to do it?

[GiudGiud]

In how many places do you need to do this?

If not too many I would recommend using two variables, a non broken mesh and an interface kernel. Having two variables makes it easy to have a discontinuity

[favinom]

Ideally, we would like to go for 100 interfaces.

The approach with two variables is doable if the interface cuts the whole domain, but I do not know if it is possible if the interface is included in the domain, as in the picture I posted above.

Maybe I can try with constraints?

However, I think the feature I need could be of interest also for someone else.

What is BreakBoundaryOnSubdomainGenerator doing?

Many thanks

[GiudGiud]

Are they ordered very regularly (like all aligned in 1D so you could alternate just two sets of variables) ?
Or is it somewhat random?

but I do not know if it is possible if the interface is included in the domain, as in the picture I posted above.

It is possible to block restrict in parts of the mesh, even if it's an inclusion and not spanning the entire domain.

Maybe I can try with constraints?

Mortar constraints are definitely a solution here. If you split the domain (e.g. use the BreakXYZMeshGenerator, that creates a non-conformal mesh)

What is BreakBoundaryOnSubdomainGenerator doing?

It does what the BreakMeshByBlock does but only along a given boundary, and creating different breakages (the breaks have non-broken nodes at each end) for each subdomain along that boundary