High order element face mesh cannot be loaded

[wgyang]

Description

When a high order mesh is used, the face mesh cannot be represented by vtp file. It should be written in an unstructured grid (vtu) file. svFSIplus uses load_vtp to read face files leading to an error when a high-order element mesh is used, for example, a curved quadratic triangle mesh. The P2 surface meshes used in the block compression test in svFSI-Tests are incorrect as they are written in vtp files. The figure below shows the face vtp file.

To support true high-order element meshes, function read_vtp needs to accept mshtype as input in addition to face type when it reads face files.

Reproduction

A tet10 mesh, svFSI.inp, and svFSI.xml are attached below for testing.
tet10_test.zip

Expected behavior

svFSIplus can read and output the high-order meshes it supports.

Additional context

No response

Code of Conduct

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[ktbolt]

@wgyang Please upload all of the files needed to run a simulation so I can test.

[wgyang]

@wgyang Please upload all of the files needed to run a simulation so I can test.

I modified my original post to include the mesh and input files.

[ktbolt]

The problem was that the read_vtp() function was expecting to read a VTP file for some reason.

I've added a check for a VTU file inread_vtp() and added a load_vtu() function that works with faces. I also needed to add vtk_xml_parser functions to store vtkUnstructuredGrid data into a face.

The simulation now runs but svFSIplus results don't match the Fortran results.

[ktbolt]

I've fixed several bugs

• indexing
• array out of bounds
• tet10 2nd derivatives
• C++ code not updated with Fortran bug fix

A bug fest for sure!

So after fixing the .inp and .xml solver files to have the same parameters the C++ and Fortran code produce the same results.

[wgyang]

@ktbolt Thank you Dave!! I can add this example to the test cases once you merge your fix into the main branch.

[ktbolt]

Thank Q @wgyang, allowed me to find several important bugs.