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January 15, 2015, 23:03 |
adaptive time stepping and convergence
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#1 |
Senior Member
Nick
Join Date: Nov 2010
Posts: 126
Rep Power: 15 |
Hi,
I was wondering if there is a way that you could set different residual convergence targets for different equations when using the adaptive time step. Is this possible? For example 1e-4 for continuity and 1e-5 for momentum etc. Thanks in advance. |
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January 16, 2015, 04:08 |
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#2 |
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Mohamad Alagheband
Join Date: Oct 2012
Posts: 41
Rep Power: 13 |
I think there is a way
in solver control setting you can adjust convergence control criteria for continuity and momentum and turbulency separately. |
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January 17, 2015, 13:36 |
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#3 |
Senior Member
Mr CFD
Join Date: Jun 2012
Location: Britain
Posts: 361
Rep Power: 14 |
No you can't do this. You can however have different schemes for advection and transient.
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January 19, 2015, 02:26 |
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#4 | |
Senior Member
Lance
Join Date: Mar 2009
Posts: 669
Rep Power: 22 |
Quote:
This example shows how to set a different convergence critera for an additional variable. 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-5 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 |
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January 19, 2015, 05:57 |
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#5 |
Senior Member
Mr CFD
Join Date: Jun 2012
Location: Britain
Posts: 361
Rep Power: 14 |
Wow, that's good to know. I take it then you must replace the CCL file in command line prior to running the simulation.
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January 19, 2015, 06:33 |
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#6 |
Senior Member
Lance
Join Date: Mar 2009
Posts: 669
Rep Power: 22 |
Yes, do it either at the command line or right before you save the .def in PRE. Note that for additional variables there is just one set of options, so it is not possible to have different convergence criteria for different AVs.
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