[gigilentini8]

Dear FOAMers,
can you confirm me that the function object below in ControlDict is the correct and fastest way to calculate average over cutting planes in a 3D simulation during runtime?
it seems to work but I'm not 100% sure about the results...

functions
{
    cuttingplane_average
    {
        type            faceSource;
        functionObjectLibs ("libfieldFunctionObjects.so");

        enabled         true;
        outputControl   outputTime;

        // Output to log&file (true) or to file only
        log             true;

        // Output field values as well
        valueOutput     false;  //true;

        // Type of source: patch/faceZone/sampledSurface
        source          sampledSurface;

        sampledSurfaceDict
        {
                type cuttingPlane;
                planeType           pointAndNormal;
                pointAndNormalDict
                {
                        basePoint       (0 0 0);  
                        normalVector    (0 0 1);
                }
                source cells; // sample cells or boundaryFaces
                interpolate true;
        }

        // Operation: areaAverage/sum/weightedAverage ...
        operation       areaAverage;

        fields
        (
            p
            U
        );
    }

[fede32]

was it right?

[Vidal]

In OF version 7 I have managed to report on runtime the average value on a cutting plane by modifying a little the above code, which is inside the "functions" sub-dictionary in the controlDict:

cuttingplane_average
{
    type            surfaceFieldValue;
    libs            ("libfieldFunctionObjects.so");
    enabled         yes;
    writeControl    timeStep;
    writeInterval   1; 
    log             yes;
    // Output field values as well
    writeFields     no;
    // Type of source: patch/faceZone/sampledSurface
    regionType      sampledSurface;
    name            sampledSurfaceNormalZ1;
    sampledSurfaceDict
    {
            type                    cuttingPlane;
            planeType               pointAndNormal;
            pointAndNormalDict
            {
                    basePoint       (0 0 1);  
                    normalVector    (0 0 1);
            }
            source cells; // sample cells or boundaryFaces
            interpolate true;
    }
    // Operation: areaAverage/sum/weightedAverage ...
    operation       areaAverage;
    fields
    (
        U p
    );
}

The changes are:
1. "type" must be "surfaceFieldValue" instead of "faceSource".
2. It is necessary to give a user "name" for the average value output ("sampledSurfaceNormalZ1" in my case.)
3. Other differences are I guess because the different OF versions ("regionType" instead of "source", "writeControl", ...).

I hope it helps.

Cheers

[olesen]

For future reference as well: if you are using OpenFOAM-v1906 or later you also have the possibility to create/sample surfaces and "store" them. This places them in memory where they can be picked up later for surfaceFieldValue and/or runTimePostProcessing.


In many cases this can be more efficient and flexible than creating the sampled surfaces from within surfaceFieldValue itself.



https://develop.openfoam.com/Develop.../-/issues/1206


https://www.openfoam.com/documentati...s.html#details