Completed all coefficient loops in transient iteration

RAJDEEP · October 17, 2019, 13:20

Hello,
I am newbie to CFX. while carrying out transient simulation, all coefficient loops (30) are getting finished for initial iterations in transient simulation.

I want to know that, will it create any incorrect transient result at that particular iteration?

And any tutorial or material regarding coefficient loops in CFX. What it is actually meant for it.

ghorrocks · October 17, 2019, 17:40

It means those time steps did not achieve your convergence criteria, so are potentially less accurate than fully converged time steps. But whether this matters depends on what you are doing. If you need to resolve the start up transient accurately then you better fix it so they fully converge. If the initial startup transient is not important then it can be ignored.

Carlo_P · October 18, 2019, 02:56

That sounds strange..
maybe you didn't initialize it correctly.
Try to run a steady simulation with the initial value, in order to have a correct starting situation.
Normally, the coefficient loops should be around 7-10.

October 17, 2019, 13:20	Completed all coefficient loops in transient iteration	#1
RAJDEEP New Member RAJDEEP JAGDALE Join Date: Oct 2018 Posts: 26 Rep Power: 7	Hello, I am newbie to CFX. while carrying out transient simulation, all coefficient loops (30) are getting finished for initial iterations in transient simulation. I want to know that, will it create any incorrect transient result at that particular iteration? And any tutorial or material regarding coefficient loops in CFX. What it is actually meant for it.

October 17, 2019, 17:40		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,727 Rep Power: 143	It means those time steps did not achieve your convergence criteria, so are potentially less accurate than fully converged time steps. But whether this matters depends on what you are doing. If you need to resolve the start up transient accurately then you better fix it so they fully converge. If the initial startup transient is not important then it can be ignored. aero_head likes this. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

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October 18, 2019, 02:56		#3
Carlo_P Senior Member Carlo_P Join Date: May 2019 Location: Italy Posts: 176 Rep Power: 7	That sounds strange.. maybe you didn't initialize it correctly. Try to run a steady simulation with the initial value, in order to have a correct starting situation. Normally, the coefficient loops should be around 7-10.