Viscous flow over a base

[wehrad]

Hi everyone,

I'm working on a mesh representing a viscous material and I'd like the latter to flow over the equivalent of a rock base/bed.

I thought of swapping all elements with the "bottom" boundary to a new subdomain ID to which I could give rock properties instead of the viscous ones and hence move the material/bed boundary one element up. But I couldn't find how to do so...

The end goal is to implement a Coulomb model at the interface between the viscous material and a rock base, at the bottom of my current mesh. But maybe there is actually a better way to do it from the beginning than changing subdomain IDs?

So far I've only found solutions for a friction law between two media that are directly described in the input mesh.

Thank you a lot in advance for your help!

[GiudGiud]

Hello

The only tool to change subdomain IDs dynamically currently is:
https://mooseframework.inl.gov/source/userobjects/CoupledVarThresholdElementSubdomainModifier.html
https://mooseframework.inl.gov/source/userobjects/CutElementSubdomainModifier.html (in XFEM module)

If you are thinking of stopping the simulation and restarting, you can use the mesh generator to change subdomain ids:
https://mooseframework.inl.gov/source/meshgenerators/ParsedSubdomainMeshGenerator.html

Guillaume

[wehrad]

Exactly @GiudGiud !

[wehrad]

In this case, the bottom layer. Or maybe it's easier to stitch an additional one but I doubt it on such a complex delineation...

[GiudGiud]

@aprilnovak @eshemon is a BoundaryLayerSubdomainIDGenerator (changes the subdomain ID near boundaries) on your radar by any chance?

Otherwise I can make it.

[eshemon]

No, we don't have that on the radar at this point. Tagging @miaoyinb for awareness if you go ahead and implement!

[wehrad]

Thanks a lot to you all! At the end for the moment I decided to subdivide my blocks at the mesh generation step, and then apply the variables, kernels etc... to each existing subdomain ID! Thank you a lot for your help!