How to set minimum number of iterations in Fluent?

Pierre1 · March 21, 2015, 01:44

Sometimes we need to set a minimum number of iterations the simulations shall run. How to set that up in Fluent? CFX has this option but I didn’t find it out in Fluent.

`e` · March 21, 2015, 06:41

If there are no settings to restrict the minimum number of iterations, then you could remove the convergence criteria, run for x iterations and then turn the convergence criteria back on.

Pierre1 · March 21, 2015, 08:36

Quote:

Originally Posted by `e`

If there are no settings to restrict the minimum number of iterations, then you could remove the convergence criteria, run for x iterations and then turn the convergence criteria back on.

Sometimes I run hundreds of simulations by Workbench. I can't do that manually for each of them. Is there a better way to achieve that?

`e` · March 21, 2015, 17:03

Ok, to automate this process, have a read of this article on using Scheme and a UDF; use the rp-variable as an iteration counter (and when it reaches x, set the convergence criteria on).

LuckyTran · March 22, 2015, 19:34

As far as I know, there's no setting for minimum number of iterations.

I've also just turned off all convergence monitors until the minimum iterations has been reached and then turned them on. This is fairly straightfoward to do using TUI or a journal file so it is not cumbersome.

It would be a nice feature to have in future versions, especially for unsteady simulations is a very useful feature to have.

Johann Möller · May 23, 2018, 11:06

Quote:

Originally Posted by LuckyTran

As far as I know, there's no setting for minimum number of iterations.

I've also just turned off all convergence monitors until the minimum iterations has been reached and then turned them on. This is fairly straightfoward to do using TUI or a journal file so it is not cumbersome.

It would be a nice feature to have in future versions, especially for unsteady simulations is a very useful feature to have.

Hi LuckyTran,

I know this a fairly old thread, but hopefully you can still help me. I am trying to do the same the same as you - turn off all my convergence monitors and only turn then on after the minimum number of iterations - but I am struggling to manage. How did you do it?

Thanks

LuckyTran · May 23, 2018, 14:33

You can't do it. You have to do it manually. That means run it with all monitors off, and then turn on the monitors and run again.

March 21, 2015, 01:44	How to set minimum number of iterations in Fluent?	#1
Pierre1 Member Pierre Join Date: Mar 2015 Posts: 37 Rep Power: 11	Sometimes we need to set a minimum number of iterations the simulations shall run. How to set that up in Fluent? CFX has this option but I didn’t find it out in Fluent.

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March 21, 2015, 06:41		#2
`e` Senior Member Join Date: Mar 2015 Posts: 892 Rep Power: 18	If there are no settings to restrict the minimum number of iterations, then you could remove the convergence criteria, run for x iterations and then turn the convergence criteria back on.

March 21, 2015, 17:03		#4
`e` Senior Member Join Date: Mar 2015 Posts: 892 Rep Power: 18	Ok, to automate this process, have a read of this article on using Scheme and a UDF; use the rp-variable as an iteration counter (and when it reaches x, set the convergence criteria on).

March 22, 2015, 19:34		#5
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,674 Rep Power: 65	As far as I know, there's no setting for minimum number of iterations. I've also just turned off all convergence monitors until the minimum iterations has been reached and then turned them on. This is fairly straightfoward to do using TUI or a journal file so it is not cumbersome. It would be a nice feature to have in future versions, especially for unsteady simulations is a very useful feature to have.

May 23, 2018, 14:33		#7
LuckyTran Senior Member Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,674 Rep Power: 65	You can't do it. You have to do it manually. That means run it with all monitors off, and then turn on the monitors and run again.