[tong]

Hi,

I have completed an analysis using twoPhaseEulerFoam solver and have some results files. My case is similar to the tutorial bubblecolumn case where bubble flows up to the outlet at the top of the domain.

I want to get a plot of the droplet size distribution at the outlet. I have found that there is a function called 'regionSizeDistribution' and there is an example showing the inputs and outputs of the function, however where and how do I implement this function? ie. do I copy, for example, this function:

regionSizeDistribution1
{
type regionSizeDistribution;
functionObjectLibs ("libfieldFunctionObjects.so");
...
field alpha;
patches (outlet);
threshold 0.4;
fields (p U);
nBins 100;
maxDiameter 0.5e-4;
minDiameter 0;
setFormat gnuplot;
}

into the controldict file and then re-run the solver again at the time I want?

Thank you in advance,
Tong

[tong]

please, any help will be great.

[tong]

Hi,

I had successfully ran the regionSizeDistribtion function in controlDict for my case which is suppose to plot a histogram of droplet sizes vs frequency they occur on a specified patch. After running the case, two new files appear in the latest time file: alpha1_background and alpha1_liquidCore. However, there was no histogram to be found anywhere. I was just wondering how does the output for regionSizeDistribution work? Where does the histogram saved to?

Regards,
Tong

[wyldckat]

Greetings Tong,

I got your private message and I'll answer here on the forum, since more people can take advantage of this.

I've tested this on the tutorial "multiphase/twoPhaseEulerFoam/bubbleColumn" and used the following "system/controDict":

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.2.2                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "system";
    object      controlDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

application     twoPhaseEulerFoam;

startFrom       startTime;

startTime       0;

stopAt          endTime;

endTime         20;

deltaT          0.002;

writeControl    runTime;

writeInterval   0.5;

purgeWrite      0;

writeFormat     ascii;

writePrecision  6;

writeCompression uncompressed;

timeFormat      general;

timePrecision   6;

runTimeModifiable yes;

adjustTimeStep  no;

maxCo           0.5;

maxDeltaT       1;

functions
{
    fieldAverage1
    {
        type            fieldAverage;
        functionObjectLibs ( "libfieldFunctionObjects.so" );
        outputControl   outputTime;
        fields
        (
            U1
            {
                 mean        on;
                 prime2Mean  off;
                 base        time;
            }

            U2
            {
                 mean        on;
                 prime2Mean  off;
                 base        time;
            }

            alpha1
            {
                 mean        on;
                 prime2Mean  off;
                 base        time;
            }

            p
            {
                 mean        on;
                 prime2Mean  off;
                 base        time;
            }
        );
    }

    regionSizeDistribution1
    {
        type            regionSizeDistribution;
        functionObjectLibs ("libfieldFunctionObjects.so");
        outputControl   outputTime;
        field           alpha1;
        patches         (inlet);
        threshold       0.5;
        fields          (p U);
        nBins           100;
        maxDiameter     0.5;
        setFormat       gnuplot;
    }
}


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

As you can see, this is essentially what's described in the Doxygen generated code documentation. Specifically, the part that was added was this:

    regionSizeDistribution1
    {
        type            regionSizeDistribution;
        functionObjectLibs ("libfieldFunctionObjects.so");
        outputControl   outputTime;
        field           alpha1;
        patches         (inlet);
        threshold       0.5;
        fields          (p U);
        nBins           100;
        maxDiameter     0.5;
        setFormat       gnuplot;
    }

As for the resulting files (available only after running twoPhaseEulerFoam with the new "controlDict"), they are located inside the folder "postProcessing/regionSizeDistribution1", more specifically inside each dedicated time folder.
Inside each one of those time folders you'll find Gnuplot scripts, which can be executed by giving them to the gnuplot command, e.g.:

gnuplot postProcessing/regionSizeDistribution1/0.5/diameter_count.gplt

The downside is that all of the plots will save the resulting plot into the file "diameter.ps".

Best regards,
Bruno

[tong]

Hi,

Are max and min diameter set to meters or millimeters by default?

Thanks