Turek-Hron FSI 3 problem - dealii not converging in first time step

Official adapters and tutorials
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#1

Hi
I’m trying to run the “Turek-Hron” tutorial provided with preCICE. I’ve followed the introduction page to the tutorial, but when I try to run it, dealii just doesn’t converge in the first time step. I’ve run the fluid case seperately and the inlet seems to work as intended. I close the following from dealii:

Timestep 1 @ 0.001s
_______________________________________________________________________________________
 SOLVER STEP     |  LIN_IT   LIN_RES    RES_NORM   RES_ABS      U_NORM     U_ABS 
_______________________________________________________________________________________
0  CST  ASM  SLV  |       1  0.000e+00  1.000e+00  2.029e-02    1.000e+00  2.595e-08  
1  CST  ASM  SLV  |       1  0.000e+00  3.142e-08  6.375e-10    2.442e-08  6.336e-16  
2  CST  ASM  CONVERGED! 
_______________________________________________________________________________________
Relative errors:
Displacement:	2.442e-08
Residual: 	6.237e-09
v / V_0:	7.020e-03 / 7.020e-03
---[precice]  relative convergence measure: relative two-norm diff of data "Stress" = 7.53e-01, limit = 1.00e-04, normalization = 1.83e+01, conv = false
---[precice]  relative convergence measure: relative two-norm diff of data "Displacement" = 3.38e-02, limit = 1.00e-04, normalization = 1.08e-08, conv = false
---[precice]  Mapping "Stress" consistent from "Fluid-Mesh-Centers" (ID 0) to "Solid-Mesh" (ID 2) for dimension 0 with polynomial set to separate
---[precice]  Mapping "Stress" consistent from "Fluid-Mesh-Centers" (ID 0) to "Solid-Mesh" (ID 2) for dimension 1 with polynomial set to separate
---[precice]  iteration: 16 of 100, time-window: 1, time: 0 of 15, time-window-size: 0.001, max-timestep-length: 0.001, ongoing: yes, time-window-complete: no, read-iteration-checkpoint

Does anyone have an idea, what I’m doing wrong? I run the following versions:
Dealii 9.4.0
OpenFOAM 2206
preCICE 2.5.0
Ubuntu 20.04

#2

Hi @AndersAaroee,

What exactly doesn’t converge? In the log you posted above, everything seems to work perfectly fine. Could you elaborate your problem more in detail and post the full log files?

#3

Hi David, thanks for your reply.

The relative convergence measure comes back false as it shows in the bottom of the log I posted. It keeps doing this until it comes to the max iteration and then proceeds (The example is at iteration 16 out of 100). In this way it can run the simulation, but I don’t believe this was how it was intented by preCICE.