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[CFX] Set convergence level for additional variable

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Old   December 14, 2010, 08:24
Default [CFX] Set convergence level for additional variable
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Lance
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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.
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Old   December 15, 2010, 08:22
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Lance
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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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