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Find X,Y,Z Location of maxVal (CFX-Post)

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Old   November 16, 2010, 17:25
Default Find X,Y,Z Location of maxVal (CFX-Post)
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I have done CFD studies previously but i am new to the CFX-post application.... I am simulating a 3D airfoil to study the wing tip vorticity of the flow in this region... I have created a table to find the max vorticity magnitude at different downstream locations using maxVal(Expression)@(Location) in the table cells... Now I want to find the X,Y,Z coordinates of this value and input them to the table i have created; however, i have not been able to do this.... Does anyone know how to do this or a different way to track the vortex core line....
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Old   November 17, 2010, 04:06
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Matthias Voß
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hi,

you can use the Point@ValueMaximum and than look for the Coord. of the Points. That´s without scripting and not for many points.
By the way, if you set set the downstream positions why do you want to know the Coord. again?

neewbie

Last edited by mvoss; November 17, 2010 at 06:44.
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Old   November 17, 2010, 11:20
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neewbie,

Thanks for your info... I set a point at the maximum value of my vorticity magnitude variable and got all the information from there... Pretty simple but as I told you I am new to this tool....
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Old   November 18, 2010, 02:55
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Hi,
You can directly go in File -> Export, Select the points generated by the software and in that select the variable related to the point which you want to export, in that window check export geometry information as well.
- Dinesh
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Old   December 22, 2010, 12:18
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Mathieu Etcheparre
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Hi,

would anyone tell me how or point me to where it is explained how this could be done for a transient simulation? Trying to get the coordinates of maxVal(Velocity)@plane 1 for each timestep for example?

thanks in advance!
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Old   December 22, 2010, 18:57
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Edmund Singer P.E.
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Create a chart or use perl script.
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Old   December 23, 2010, 09:17
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Mathieu Etcheparre
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Hi,

Thanks for the reply!
I've been playing around with the chart tool but haven't been able to obtain x,y,z values for my maxVal.

Do you think you help me out a bit with the script, I've never used this method before?

Also I read I could achieve this using a FORTRAN subroutine, any ideas/help on this?

once again thanks in advance!

EDIT

Found how to do it:

Define a point by the min or max of your variable.
Create a new expression: probe(y)@point 1
Create a chart of the expression as a function of time and voila...

thanks for your help!

Last edited by cheche; December 23, 2010 at 10:49.
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Old   December 23, 2010, 11:09
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Edmund Singer P.E.
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It is best to do this with a chart. Just transient chart the expression, with x being time. It will cycle through and get your results for you.

If you want to forge ahead with perl, see below. There is logic in that script to skip some timesteps (we didnt want to pull data from every transient file).

DATA READERATA READER
Current Results File = Design_1_3_002.res
Current Timestep = -1
Clear All Objects = false
Keep Camera Position = true
Force File Reload = true
END
> load
#
# loop on results
#
!for ($i=0;$i<=20; $i++){
#
!$resstp=75 + 30 * $i;
#Load in Time step
#Time Step
USER SCALAR VARIABLE:Timewrite
Boundary Values = Conservative
Calculate Global Range = Off
Expression = Time
Recipe = Expression
END
#
#
EXPRESSION EVALUATOR:
Evaluated Expression = Time
END
> forceupdate EXPRESSION EVALUATOR
DATA READERATA READER
Current Timestep = $resstp
END
> load
#
!($VolTime, $tunits) = evaluate('volumeAve(Timewrite)@Domain 1');
#
#Volume Averaged Pressure
!($VolPres, $units) = evaluate('volumeAve(Pressure)@Domain 1');
!print OUTFILE "$VolTime $VolPres\n";
!}
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