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-   -   [CFX] Set convergence level for additional variable (http://www.cfd-online.com/Forums/cfx/83084-cfx-set-convergence-level-additional-variable.html)

 Lance December 14, 2010 08:24

[CFX] Set convergence level for additional variable

Hi,
Im running LES and have set my convergence level to 1e-6 which the solver reaches within a couple iterations. However, I have an additional variable and it takes about 10-15 iterations per time step for it to reach 1e-6.

So, in order to speed up my simulation, I want to set a lower convergence level for the additional variable. Is that possible? I know that Fluent has the option to specify convergence level on each equation, it would be great if CFX also had that option.

 Lance December 15, 2010 08:22

Update:
got some help from support, and yes, its possible to have different convergence criteria for AVs. Just edit the CCL like:
Code:

```FLOW: Flow Analysis 1 SOLVER CONTROL:   Turbulence Numerics = First Order   ADVECTION SCHEME:     Option = High Resolution   END   CONVERGENCE CONTROL:     Maximum Number of Coefficient Loops = 10     Minimum Number of Coefficient Loops = 1     Timescale Control = Coefficient Loops   END   CONVERGENCE CRITERIA:     Residual Target = 1.E-6     Residual Type = RMS   END   EQUATION CLASS: av     ADVECTION SCHEME:       Option = High Resolution     END     CONVERGENCE CRITERIA:       Residual Target = 1.E-3       Residual Type = RMS     END     TRANSIENT SCHEME:       Option = Second Order Backward Euler     END   END   TRANSIENT SCHEME:     Option = Second Order Backward Euler     TIMESTEP INITIALISATION:       Option = Automatic     END   END  END END```
There will be an error message in CFXpre: "Convergence criteria....not physically valid", but just ignore it, and it will work - at least it does for me.

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