Configuring FSI3 with Face-centered tractions/stresses instead of Node-centered forces

Dear preCICE community,

I have successfully coupled our in-house finite-volume CFD solver with preCICE 3 and am currently running the FSI3 test case from Turek, using CalculiX as the structural solver.

Forces and displacements are exchanged, with constant under-relaxation as the acceleration method. The FSI coupling performs well using the serial-implicit scheme, and the results are satisfactory.

I would like to work with tractions/stress/pressure at face centers instead of forces at the nodes. Has anyone configured the FSI3 case with CalculiX in this way? If so, I would appreciate any guidance or insights on how to achieve this.

Thank you in advance for your help!

Best regards,
Guillaume De Nayer

Hi Guillaume,

That’s good news!

For preCICE, there is no difference whether you use data at face centers or nodes. Both are, first, only a cloud of points. Only if you want to use a nearest-project mapping, mesh connectivity comes into play.

Which mapping are you using or do you want to use?

There is:

Benjamin

Hi Benjamin,

Regarding the mapping, I’m using rbf. The thin-plate-splines or compact-tps-c2 rbf mappings are working well with FSI3 case exchanging forces.

Now, I want to exchange stress. The preCICE mapping seems not be a problem. The CalculiX configuration has to be modified. If I correctly understand, CLOAD (concentrated load) should be replacement by DLOAD (distributed load) in the CalculiX input file. And the config.yml should contains “pressure” associated with “faces-mesh” instead of “forces” with “nodes-mesh”. But until now I did not find the way to modify my CalculiX files, so that it works…

These CalculiX details are unfortunately not my expertise. I hope you can borrow sth from the PRs mentioned above.