[er99]

Hi all,

I have inherited a code which includes the following sampling lines below within the controlDict file.
Does anyone know how the plane areaAverage operation works in OpenFOAM? What's the equation which describes this particular operation?

Would really appreciate your help!

Thanks in advance.

 
    {
       type            surfaceRegion;
       libs ("libfieldFunctionObjects.so");
  
        enabled         true;
	writeControl    runTime; 
	writeInterval   0.001;
        log             false;
        writeFields     false;
	writeArea       false;
        surfaceFormat   none;
        regionType      sampledSurface;
        name      Mean;

	sampledSurfaceDict
         {
               type        plane;
	       basePoint   (0.1524 0 0);
	       normalVector (1 0 0);
	 }
          operation       areaAverage;
          fields
          (
	     rho
          );
      }

[tecmul]

Hi, the areaAverage operation is defined in (for OpenFOAM 6):

src/functionObjects/field/fieldValues/surfaceFieldValue/surfaceFieldValueTemplates.C

Here's the piece of code for areaAverage:

        
       case opAreaAverage:
        {
            const scalarField magSf(mag(Sf));

            result = sum(magSf*values)/sum(magSf);
            break;
        }

magSf is defined as a scalar field of face normal vector magnitudes. The rest is just the area weighted average of whatever field you choose to integrate (rho in your case) over the plane specified by the sampledSurfaceDict. surfaceFieldValueTemplates.C also has some code related to interpolation of the field onto the plane which I don't understand.