Stability and convergence issue in restarting a simulation (svFSI solver)

[sarazeta96]

Description

Is it normal for the solvers from svFSI to struggle with convergence (see the lsIt column) during the first timesteps immediately after a restart? Also, is it common for the pressures and flows in the "B_FS_....txt" files to exhibit sudden, strange peaks and values? I don't know if this is related to the type of solver or the type of simulation (this one is from a "moving wall" setting).

Right before stopping the simulation with "STOP_SIM" file:

After the restart:

Plot of Flow/pressures profiles:

Why did it cause such peaks in the pressure and flow profiles (see red box on the plot)? The peaks wouldn't have been created if I hadn't stopped the simulation with "STOP_SIM" (I did a test on that).

Reproduction

I am using the FSI equation (LS type: GMRES - Preconditioner: FSILS)
and mesh equation (LS type: CG - Preconditioner: FSILS)

With a condition of "moving wall" :
Type: Dir
Time dependence: General
Temporal and spatial values file path: Wall_movBc.dat

histor.txt

Boundary conditions are: zero pressure outlets and flow curve at the inlet.

Expected behavior

Not creating those peaks in the plot and not having convergence issues in the first timesteps after the restart

Additional context

No response

Code of Conduct

• I agree to follow this project's Code of Conduct and Contributing Guidelines