Espression defining the difference to a "X iterations mean" of another expression

germinal · September 1, 2016, 14:10

Hi :-)

I'm simulating a fan and I would like to stop the simulation when the "difference from mean" massFlow at outlet is equal 0 for a number of iterations.

Is there a way to define an expression (CFXpre) that gives the difference to mean of X iterations of an another expresion - as masFlow or areaAve of pressure...etc...?

Thank you!

Cheers

Bruno

Opaque · September 1, 2016, 16:41

Which version of the software are you using ?

There is a newer mechanism to evaluate the "moving standard deviation" of an integrated expression such as the mass flow.

germinal · September 3, 2016, 10:20

Sorry!

ANSYS 17.1

No idea how can I do it.

Cheers :-)

Opaque · September 5, 2016, 15:49

Create a monitor point, option = Expression and you should see the possibilities of evaluating several statistics on such expression.

germinal · September 8, 2016, 09:59

Hi Opaque

:-) yeah...thank you.

Actually I just need an "interrupt control" based on the monitor point. I am sure there is a way to do that (playing with the actual iteration) taking into account the statistics.

The question is how :-)

Cheers

B.

PeMo · September 9, 2016, 03:26

You can access the statistics of monitor points with the "probe" command, e.g.: probe(Expression.Value.Arithmetic Average)@Monitor Point. Check the documentation for further details.
Then set it as an interrupt condition

September 1, 2016, 14:10	Espression defining the difference to a "X iterations mean" of another expression	#1
germinal New Member Björn Join Date: Aug 2010 Location: Zürich Posts: 18 Rep Power: 16	Hi :-) I'm simulating a fan and I would like to stop the simulation when the "difference from mean" massFlow at outlet is equal 0 for a number of iterations. Is there a way to define an expression (CFXpre) that gives the difference to mean of X iterations of an another expresion - as masFlow or areaAve of pressure...etc...? Thank you! Cheers Bruno

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September 1, 2016, 16:41		#2
Opaque Senior Member Join Date: Jun 2009 Posts: 1,880 Rep Power: 33	Which version of the software are you using ? There is a newer mechanism to evaluate the "moving standard deviation" of an integrated expression such as the mass flow.

September 3, 2016, 10:20		#3
germinal New Member Björn Join Date: Aug 2010 Location: Zürich Posts: 18 Rep Power: 16	Sorry! ANSYS 17.1 No idea how can I do it. Cheers :-)

September 5, 2016, 15:49		#4
Opaque Senior Member Join Date: Jun 2009 Posts: 1,880 Rep Power: 33	Create a monitor point, option = Expression and you should see the possibilities of evaluating several statistics on such expression.

September 8, 2016, 09:59		#5
germinal New Member Björn Join Date: Aug 2010 Location: Zürich Posts: 18 Rep Power: 16	Hi Opaque :-) yeah...thank you. Actually I just need an "interrupt control" based on the monitor point. I am sure there is a way to do that (playing with the actual iteration) taking into account the statistics. The question is how :-) Cheers B.

September 9, 2016, 03:26		#6
PeMo Member Peter Join Date: Sep 2011 Location: Germany Posts: 39 Rep Power: 15	You can access the statistics of monitor points with the "probe" command, e.g.: probe(Expression.Value.Arithmetic Average)@Monitor Point. Check the documentation for further details. Then set it as an interrupt condition