Is is possible to couple a solver to preCICE that provides only average values over a volume element? That is, I have a solver that provides its solution as average values over a volume rather than values on faces or at vertices. It looks like the only interface for reading/writing coupling data operates at the level of vertices, so I’m wondering if this is perhaps just not possible with preCICE.
As an example, here is a quick image of a solution showing heat deposition over a region. This is actually a 3D problem, so what appears as squares here are really cubes (hexahedra). I also noticed that the only interface for 3D connectivity is for tetrahedra, so I’m also wondering if using hexahedra is a possibility.
You could define the cell centres as vertices and write the cell data to those cell centres. Then either use a consistent or conservative mapping depending on your use case. If you deal with matching meshes, then this scenario should be as easy as defining a nearest-neighbour mapping. Otherwise, you may need to use RBF mappings.
Many things are possible with preCICE. A good understanding of the solver and some creativity in the adapter can solve most problems. Brainstorming at the preCICE workshop is also pretty effective.
Yes it is possible. It requires you to decompose the hexahedral into tetrahedral elements and pass them to preCICE.
We learned from the Quad support, that preCICE needs to make too many assumptions order to provide a useful implementation. Having knowledge of the solver makes the decomposition often substantially easier. Therefore, we decided to let the user decompose the mesh.
