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Error: CSysSolve linear solver diverged

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Old   November 19, 2020, 08:39
Default Error: CSysSolve linear solver diverged
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Hello everybody, I am trying to run a turbulent simulation with RANS solver and the same error keeps showing up:

Error in "void CSysSolve<ScalarType>::ModGramSchmidt(int, su2matrix<ScalarType>&, std::vector<CSysVector<ScalarType> >&) const [with ScalarType = double; su2matrix<ScalarType> = C2DContainer<long unsigned int, double, (StorageType)0, 64, 0, 0>]

FGRMES orthogonalization failed, linear solver diverged

I have already tried to change the CFL number, the slope limiter, the type of linear solver, convergence criteria and all the other parameters, but nothing works.

Does anyone have an idea of what might be happening here?
Thanks in advanced
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Old   November 29, 2020, 00:43
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Is it happening at the start or after few iterations ?

Make sure that your mesh is of acceptable quality and boundary conditions are correctly applied (at times mesh quality causes such divergence issue). Having said that, give a try to -

LINEAR_SOLVER= BCGSTAB
LINEAR_SOLVER_PREC= ILU
LINEAR_SOLVER_ITER= 5 or 10 (if needed) (In one case, these setting helped me to overcome the similar issue)

You can also try first order simulation followed by second order (restart from first) and see if it helps. Also switch off the multigrid (if turned on).
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