I have a question regarding the element types I can use in FSI coupling between OpenFOAM and CalculiX. I recently run some tests with linear and second FE elements. The cases converge but the results seem different and I wonder if second order elements can be used in the coupling at all:
Typically, in FEA second order (Tet) elements are used, as they give more accurate results compared to linear elements (in particular linear Tets) and are more flexible in meshing complex geometries. In a FSI analysis in most cases the deformation of the structure takes place by the fluid pressure. If I would like to transfer the (fluid) pressure to forces for second order elements, as far as understood care has to be taken regarding the force distribution on the different nodes (distinguish between corner node and node on edge).
I wonder if this kind of weighting (to distinguish between corner nodes and edge-nodes) is considered in preCICE for second order FE-elements or if there is no need to consider this (e.g. in a conservative nearest-projection coupling).