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-   -   Expert Parametrs doubt CFX (https://www.cfd-online.com/Forums/cfx/158732-expert-parametrs-doubt-cfx.html)

TallesC September 2, 2015 09:56

Expert Parametrs doubt CFX
 
Guys, I'm working on a hard reactive system monofasico.Logo at the beginning occurs the following problem:
Newton's method warnings at: END OF TIME STEP |
+ ------------------------------------------------- ------------------- +
+ ------------------------------------------------- ------------------- +
| |
| Newton's method failed to converge while computing the variables |
| Listed below. In each case, the solver continued with the variable |
| The field it was on the last iteration. |
| |
| If this situation persists, you might try decreasing the Newton |
| Iteration underrelaxation factor. This can be changed by setting |
| Following one of the parameters for your mixture: |
| |
| Temperature: "Constitutive Relation Under Relaxation" |
| Pressure: "Newton Under Pressure Relaxation" |
| |
+ ------------------------------------------------- ------------------- +
| |
| Location Name: Serpentine |
| Mesh location: Vertex |
| Routine: UPD_LOCALE_PROP1 |
| Partition: 12 |
| Variable Name: Temperature |
| Last 3 Changes: 1.01653E 1.15153E + 30 + 30 + 30 1.09939E |
| Tolerance: 1.0000E-02 |
| Status: Diverging |
| Max Iterations: 100

already checked the fluid properties, expressions, boundary conditions. one option would be acting on expert parameters Does anyone know where I can change the expert parametrs the following variables pressure and temperature?

ghorrocks September 2, 2015 19:02

I would look at numerical stability problems before the expert parameters. Try double precision numerics, better mesh quality, a better initial condition and/or smaller time steps.

Goenitz May 16, 2019 08:32

Quote:

Originally Posted by TallesC (Post 562165)
Guys, I'm working on a hard reactive system monofasico.Logo at the beginning occurs the following problem:
Newton's method warnings at: END OF TIME STEP |
+ ------------------------------------------------- ------------------- +
+ ------------------------------------------------- ------------------- +
| |
| Newton's method failed to converge while computing the variables |
| Listed below. In each case, the solver continued with the variable |
| The field it was on the last iteration. |
| |
| If this situation persists, you might try decreasing the Newton |
| Iteration underrelaxation factor. This can be changed by setting |
| Following one of the parameters for your mixture: |
| |
| Temperature: "Constitutive Relation Under Relaxation" |
| Pressure: "Newton Under Pressure Relaxation" |
| |
+ ------------------------------------------------- ------------------- +
| |
| Location Name: Serpentine |
| Mesh location: Vertex |
| Routine: UPD_LOCALE_PROP1 |
| Partition: 12 |
| Variable Name: Temperature |
| Last 3 Changes: 1.01653E 1.15153E + 30 + 30 + 30 1.09939E |
| Tolerance: 1.0000E-02 |
| Status: Diverging |
| Max Iterations: 100

already checked the fluid properties, expressions, boundary conditions. one option would be acting on expert parameters Does anyone know where I can change the expert parametrs the following variables pressure and temperature?

same problem.. have you solved it?

ghorrocks May 16, 2019 18:20

It is unlikely you got this problem from the same method as the previous post. As I said before, this is a sign of numerical instability, so you should look at issues which contribute to numerical instability.


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