Hey!

I have a question about the IQN-ILS filter, since I am experiencing some trouble with it. In the figure, I have made a sketch of the situation. Case 1 works very well! However, when I increase the number of solvers, see Case 2. I cannot obtain well convergence. The arrows in the figure indicate the coupling variable. So for the Nutils solver, a temperature is put on the boundary and it gives a heat flux back to the OpenFOAM solver. For Nutils2, this is switched around.

The log files are posted here.

precice-OpenFOAM-convergence.log (63.8 KB)

precice-OpenFOAM-iterations.log (263 Bytes)

It starts of well, however then it sort of ‘freezes’ at values in the time steps where 120 iterations is reached. (this is the maximum amount of iterations it can do)

My precice config is posted here:

precice-config.xml (5.7 KB)

Note, that Nutils2 has variables called Temperature4 and Heatflux4 (this was a slight typing mistake). I am also not underrelaxaing the heat flux for solver 2. Is 5 variables too much for such an iterator scheme? or am I missing something to help convergence. I am confused, since for 2 solvers it worked perfectly fine.

Thank you in advance! If anything is unclear, let me know!

Kind regards,

Cars