Automatic vs automatic with value initialization

Julian121 · April 6, 2019, 13:40

When a transient simulation is initialized by a result file, does it differ to choose automatic or automatic with value if no initial condition other than the result file is specified?

ghorrocks · April 7, 2019, 00:40

Automatic with value means that if it can get this from the initial results file it will use that value, otherwise it will use the defined value.

If your initial conditions file does not specify a required variable and you have that variable set as automatic then that variable's initial condition will not be specified and the simulation will stop with an error.

Julian121 · April 7, 2019, 03:12

If I don’t specify any value under global and domain initialization and choose automatic with value and if a required value does not exist in the result file, will it assume zero?

If I stop a transient simulation which has been already initialized by a result file and then restart it, will I need to uncheck the initialization with initial condition since the run has already been initialized?

Which one is correct?

uncheck the initialization by initial condition and select current solution data

or

check the initialization by initial condition and choose the result of the transient simulation as the initial condition and check continue the history

ghorrocks · April 7, 2019, 06:47

Can I ask why are you asking this question? A simple experiment by just trying what you ask will answer these questions yourself. Why trust the dodgy memory of somebody you have never met (ie me) when you can figure it out yourself and have no doubt about it?

Gert-Jan · April 7, 2019, 09:43

I also suggest to make a backup at zero iteration. Then in Post you can find out yourself what CFX makes of the settings you choose.

April 6, 2019, 13:40	Automatic vs automatic with value initialization	#1
Julian121 Senior Member Join Date: Aug 2012 Posts: 269 Rep Power: 16	When a transient simulation is initialized by a result file, does it differ to choose automatic or automatic with value if no initial condition other than the result file is specified?

April 7, 2019, 00:40		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 18,011 Rep Power: 146	Automatic with value means that if it can get this from the initial results file it will use that value, otherwise it will use the defined value. If your initial conditions file does not specify a required variable and you have that variable set as automatic then that variable's initial condition will not be specified and the simulation will stop with an error. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

April 7, 2019, 06:47		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 18,011 Rep Power: 146	Can I ask why are you asking this question? A simple experiment by just trying what you ask will answer these questions yourself. Why trust the dodgy memory of somebody you have never met (ie me) when you can figure it out yourself and have no doubt about it? __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

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April 7, 2019, 03:12		#3
Julian121 Senior Member Join Date: Aug 2012 Posts: 269 Rep Power: 16	If I don’t specify any value under global and domain initialization and choose automatic with value and if a required value does not exist in the result file, will it assume zero? If I stop a transient simulation which has been already initialized by a result file and then restart it, will I need to uncheck the initialization with initial condition since the run has already been initialized? Which one is correct? uncheck the initialization by initial condition and select current solution data or check the initialization by initial condition and choose the result of the transient simulation as the initial condition and check continue the history

April 7, 2019, 09:43		#5
Gert-Jan Senior Member Gert-Jan Join Date: Oct 2012 Location: Europe Posts: 1,995 Rep Power: 29	I also suggest to make a backup at zero iteration. Then in Post you can find out yourself what CFX makes of the settings you choose.