[Nicola_Fontana]

Good evening,
I am new to CFD, I am working on different simultation for my master thesis, and I found some problem in the convergence of the solution, precisely in the section " CONVERGENCE PARAMETERS ". In the first attempt I encountered a problem with FMGRES convergence, as follow:

FGMRES orthogonalization failed, linear solver diverged.

I was able to solve this switching off MULTIGRID option. But even so the program does not converge to a solution:

Maximum number of iterations reached (ITER = 10000) before convergence.

I know that each situation has better convergence method that can lead to a faster ( and more precise ) solution. From test-case and other topic here in the forum I was able to find some suggestion and indication for few of all the methods listed in SU2, but for me is still difficul (almost impossible) understand how to choose the method and set the coefficient. I found papers describing the theory behind every method, and while it helped me understand the methods, it didn't help me understand how to choose.

Can someone suggest me a guide for understand how to make the choice of method and coefficient?


In general, I have the same problem with the section:

-COMMON PARAMETERS DEFINING THE NUMERICAL METHOD
-LINEAR SOLVER DEFINITION
-FLOW NUMERICAL METHOD DEFINITION

I would ask if anyone could help me, or suggest me a good way to learn and understand the use of the different method, thank you in adnvance,

Nicola