FSI 3D Upgrade

This page follows on from the standard FSI installation instructions. Follow those instructions first before continuing with this page.

If you experience any issues, please let Nik Lebedenko know.

Modify the adapter for 3D FSI

Download all the files from this GitHub repository using git clone https://github.com/cuspaceflight/fsi-3D-upgrade

Locate this installation location of your FEniCS-preCICE adapter using python3 -m pip show fenicsprecice

Navigate to this location, in my case: cd /home/nik/.local/lib/python3.8/site-packages/fenicsprecice

Replace each file in your installation location with the version found in fsi-3D-upgrade/fenicsprecice-3D

Verify everything is working correctly

Navigate to the perpendicular-flap-3D tutorial case downloaded from the GitHub repository earlier.

Navigate to the solid-fenics folder and do ./run.sh - there should be no errors, and the output should pause after a short setup period.

Now open another Ubuntu terminal, and navigate to the fluid-openfoam folder and do ./run.sh

Both terminals should now have command outputs flying, similar to the original 2D tutorial case you ran when installing the 2D FSI software.

After 2-3 mins, both terminals should stop. View the results in ParaView, and verify it looks similar to the original 2D tutorial case.

View the fluid domain by navigating to fluid-openfoam and running paraview.exe fluid-openfoam.foam

View the solid's displacement by navigating to solid-fenics and running paraview.exe Solid/FSI-S/u_fsi.pvd

• By default, the solid will appear stationary. To visualise its movement, add a "Warp By Vector" filter with the Displacement vector and scale factor 1.

Install mesh conversion software

FEniCS sadly does not natively support the import of ANSYS or OpenFOAM meshes, so a workaround must be used to generate its .xml mesh files.

Install meshio with all optional dependencies using python3 -m pip install meshio[all]

Download the foamToFenics OpenFOAM case from the GitHub repository (should already be present).

Convert between ANSYS mesh and FEniCS mesh

1. Export the ANSYS mesh as .msh
2. Open an Ubuntu terminal, navigate to the foamToFenics OpenFOAM case, and copy the .msh file there.
3. Import the mesh with fluentMeshToFoam <your msh file>, replacing <your msh file> with the full filename and extension of your .msh file.
4. Run ./exportFenics

Convert between OpenFOAM mesh and FEniCS mesh

1. Open an Ubuntu terminal and navigate to the foamToFenics OpenFOAM case.
2. Copy the polyMesh directory from your OpenFOAM case with your mesh into foamToFenics/constant
3. Run ./exportFenics