[bikalpa10]

Hello every one,

I am running an In-compressible RANS model for a 3D wing at Re 10^5. And I am facing an error with linear solver divergence in version 7.0.7, and 7.0.8. Whereas it was running fine in 7.0.6.

I have also attached Log output for both cases.
Is there an additional setting I need to add to the configuration file for SU2_7.0.7?
(note: I am using same configuration file and mesh for both the version )


Thank You
Regards
Bikalpa Bomjan Gurung

[pcg]

Hello,
The case was not running very well, the residual only drops one order of magnitude in 2000 iterations. You can try using a lower CFL, or allowing more linear solver iterations, or using the adaptive CFL.

The change in 7.0.7 likely to cause the slightly different behaviour is this one: https://github.com/su2code/SU2/pull/1059
You can try adding the following lines to the config:
PARMETIS_TOLERANCE= 0.05
PARMETIS_POINT_WEIGHT= 1
PARMETIS_EDGE_WEIGHT= 0

But like I said I think your case is not converging properly which causes it to be sensitive to minor numerical aspects, for example changing the number of cores.

[bikalpa10]

Hello Pedro,

Thank you for your suggestion, I applied it regarding Partitioning, but the solution still diverged.

Also, I did perform simulation at CFL = 5, for Linear solver, max iteration 10 and 50.
Both the case diverged and the solution for both the max iteration 10 and 50 were exactly the same with the following error message. (I have attached the output log )

Error Message:

Error in "void CSysSolve<ScalarType>::ModGramSchmidt(int, C2DContainer<unsigned long, ScalarType, StorageType::RowMajor, 64UL, 0UL, 0UL> &, std::vector<CSysVector<ScalarType>, std::allocator<CSysVector<ScalarType>>> &) const [with ScalarType = double]":
-------------------------------------------------------------------------
FGMRES orthogonalization failed, linear solver diverged

Thank you
Bikalpa