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-   -   GET_GVAR operations? (http://www.cfd-online.com/Forums/cfx/19783-get_gvar-operations.html)

Cujo July 20, 2003 16:56

GET_GVAR operations?
 
Hi, I want to use the GET_GVAR subroutine to extract the integrated value of the variable REAC_RC1_FL1. When using GET_GVAR I won't have troubles when running my problem in a parallel setup.

Does someone know the operation-name that I need to put in the "OPER" field of the GET_GVAR routine, in order to integrate the variable over the domain. I only saw examples in which ARITH_AVE was used to obtain an average (however, NOT a volume-weighted average, unfortunatelly.

Can someone help me? I'm also interested in a complete list of the possible operations of GET_GVAR, since I think it's a very convenient subroutine.

Neale July 22, 2003 00:06

Re: GET_GVAR operations?
 
What you really need is CEL access to the reaction rates, not documentation of GET_GVAR. This is an internal subroutine, not for general user usage.

At any rate, either VOLW_AVER or VOLMW_AVER should work I think.

Neale.

cujo July 22, 2003 10:19

Re: GET_GVAR operations?
 
Yup, it works. I found a list of the possible operations of GET_GVAR. For your information:

GVAR_OPER:

Mass integral: MASS_SUM Volume integral: VOLMW_SUM Max value: MAXIMUM Min value: MINIMUM Sum: ARITH_SUM Mean: ARITH_AVE Area integral: AREAW_SUM Volume average: VOLMW_AVE RMS average: RMS_AVE Area average: AREAW_AVE Mass integral: MASSW_SUM Mass average: MASSW_AVE Area: AREA

I can't find the correct name to get the reaction rate via the CEL. I tried a lot of possibilities, the most logical would be the name it has in CFX Post, but this doesn't work (I can get every other variable). I can get the reaction rate directly from the CFX MMS, but this is only possible at the end of a timestep AND when the full transient results file is available (I don't want this because of disc space limitations. I could of course write a procedure to delete the trn file every hour or so). The reaction rate seems like a very strange variable to me. I think it is calculated by CFX in a sort of post-process step. Anyway, I got it working now using GET_GVAR.

Neale July 23, 2003 11:27

Re: GET_GVAR operations?
 
You don't need to use GET_GVAR at all in 5.6. You must be using 5.5.1. or 5.5. For example, in 5.6 you can
could monitor the volume integral of a reaction rate with:


MONITOR POINT: p2
Option = Expression
Expression Value = volumeInt(Hydrogen Oygen.reacrate)@domainname
END


So, no need to use GET_GVAR. The reaction name in 5.6 is simply the object name for the reaction:


REACTION: reaction name
....
END


So, you can just use:

MONITOR POINT: p2
Option = Expression
Expression Value = volumeInt(reaction name.reacrate)@domain
END

You can also do volumeAve if you want. The volume call backs also work on subdomains as well if you only want the average or integral on part of your domain.

The call back functions are all documented.

Neale.


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