CFD Online Discussion Forums - How can I calculate fieldAverage in post-processing?

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How can I calculate fieldAverage in post-processing?

Dear all,

I have got results of a chtMultiRegionFoam (2.0.x) simulation and I'd like to calculate a fieldAverage of T in a given region. Does anybody know how to do that?

I know, that it is easy with function objects... but how do I call those during post processing?

Thanks a lot for your help!
Best,
Moritz

Hi,

in my experience, nothing is easy in OF!

I had a similar problem a couple of months ago with a simple case (no multi region and stuff). Always start from the simplest problem and advance forward from that point - I nice advice that I always forget ...

I checked the work around in my multi region case and the solution is:
- make a separate file for post processing in the systems folder
- this file should contain the FoamFile header and the functions.
- didn't figure it out how to handle multiple domains simultaneously, so stick with one
- the simpleFunctionObject worked for me, other postproc sampling didn't

@systems/postproc

Code:

/*--------------------------------*- C++ -*----------------------------------*\

| =========                 |                                                 |

| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |

|  \\    /   O peration     | Version:  2.0.0                                 |

|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |

|    \\/     M anipulation  |                                                 |

\*---------------------------------------------------------------------------*/

FoamFile

{

    version     2.0;

    format      ascii;

    class       dictionary;

    location    "system";

    object      controlDict;

}

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //



functions

{

    T_air

    {

        type volumeAverage;

        functionObjectLibs ( "libsimpleFunctionObjects.so" );

        region "air";

        fields ( T );

        factor 1.0;

        verbose true;

    }

}



// ************************************************************************* //

Code:

execFlowFunctionObjects -dict postProc -noFlow -latestTime -region air

Any addition, suggestion, improvement would be welcome.

Dear Toorop,

thanks for the reply. I was not aware of execFlowFunctionObjects. In my version of OF it does not accept the options -region and -noFlow which is why it won't work for my current problem. But in the future I will use OF 2.1 and there the options are available!

Thanks again for the hint!
All the best,
Moritz

Hi Moritz,

I have 2.0.x as well so this shouldn't be an issue. Maybe an update to your current 2.0.x would solve the problem so make a git pull and a quick rebuild.

Code:

cd $WM_PROJECT_DIR

git pull

wcleanLnIncludeAll

./Allwmake