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February 2, 2011, 19:39 |
Startup Additional Variables
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#1 |
New Member
FM
Join Date: Feb 2010
Posts: 14
Rep Power: 16 |
Hi
I'm trying to simulate a problem which requires an Additional Variable "av". The domain's DENSITY is a function of this av: DENSITY = f (av). This av is a function of TEMPERATURE: av = f (TEMPERATURE). I give the initial temperature, but at the initialization of the run, appears an error: "Error processing expression 'Density'. The expression is invalid because: Dano is not available for use in this term" I think this is because I didn't find anywhere to put an inital value of the av. Where can I initialize the av? If I can't, what can I do? Thanks |
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February 3, 2011, 14:44 |
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#2 |
Senior Member
Join Date: Mar 2009
Location: Europe
Posts: 169
Rep Power: 17 |
To be honest: i do not fully understand what you intend to do.
There are different kinds of av. If you chose the option transport equation it is possible to initialize. The type algebraic equation should depend on other variables, so it is not required to initialize.
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February 3, 2011, 18:49 |
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#3 |
New Member
FM
Join Date: Feb 2010
Posts: 14
Rep Power: 16 |
My av is an Algebraic Expression. Like I said: Density = f (av) and av = f (T).
I think the problem is because the CFX initializes first its own variables (like Temperature, COndutivity, Density...); but my Density is a function of the av created, that is initialized olny after this primitive variables. I don't know if the problem is this... Can anyone help? Thanks |
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February 4, 2011, 05:33 |
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#4 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,703
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I can't check this but I suspect you cannot made density a function of a additional variable. There are only limited variables you can make density a function of. You will have to specify density as a direct function of temperature.
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March 28, 2011, 22:59 |
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#5 | |
New Member
eric
Join Date: Nov 2010
Location: Vancouver, Canada
Posts: 16
Rep Power: 15 |
Quote:
Glenn, do you think it is possible to solve this problem by using subroutine in CFX? Actually I donot understand why CFX has such a limitation, is it because CFX can not initialize the density if additional variable is included? |
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