Is mFem the good tool for mesh smoothing for CFD polyhedral mesh?

[otaolafranc]

Hello,
I have never done FEM, but I do CFD simulations in OpenFOAM. generally with structured meshes and hybrid meshes (structured dominant+unstructured tet and pyr). in the case of structured meshes, I create them by utilities like blockMesh and salome, right now, my main issue is not the block nor the mesh creation but the smoothing of the final mesh. this brought me to search different possibilities of mesh smoothing in open source realm. but the options are quite scarce, and a collegue pointed me at mFem, which i did not know until then. I would like to ask to more experienced people with this library if the mesh smoothing of mfem would be a correct tool for this. in general for non-polyhedra meshes, i generally try to optimize the scaled jacobian which gives great results.
any inputs on this issue?
thanks in advance!

[tzanio]

Hi @otaolafranc,

MFEM can be used to smooth (unstructured) meshes made out of tets, hexes, 3-sided prisms and 4-sided pyramids in 3D. We do not currently support general polyhedra, though there have been some efforts in this direction.

In addition to smoothing, you can also use MFEM to build applications in many fields, including CFD, see the Navier miniapp.

Hope this helps,
Tzanio

cc: @kmittal2, @vladotomov, @rainiscold, @jandrej

[otaolafranc]

Thanks for your kind answer!
I have my own vtk ascii writer so, in theory my meshes (the ones i generally work with, hexas+some pyrs+tetras+prisms) should be compatible from what I saw in the doc, this is awsome!.
for better comprehension surface smoothing == smoothing the external nodes without modification of the overall boundary of the mesh.
if I may, I have some questions,

1. I see that in the doc it is mentionned nurbs, does this mean that we can use b-rep files for the smoothing of the nodes on the surface, by associating it with a b-rep face (or edge) so the node is always projected to the face (or edge)?
2. bis if not, is there any way to smooth out the 'external nodes' of the mesh? while respecting the boundary of the original mesh?
3. are there any examples on smoothing a vtk mesh? (ideally with surface smoothing also)
4. are there different smoothing algorithms? i have tested centroidal and laplacian smoothing and with some of my meshes this kind of smoother behaves badly as it tends to 'contract' the mesh.
   thanks in advance!