[pela145]

Hello!

I am modelling a 3D flow field around a building with the K-epsilon and k-omega SST models. One thing that i would like to analyse is how the initial velocity profile develops before getting to the building. I have read that the initial profile usually decreases its energy since it starts to move from the inlet boundary.

That's why I have planned to use the fieldValueDelta function in order to measure how big is the difference between U at the inlet and just a few meters before the building. I have been reading the fieldValueData.H file, where it is explained what must be added to the controlDict file. However,as I have seen, it needs to set 2 additional fieldValue functions inside of it, which I cannot find any useful information about.

I have found the fieldValue.H and fieldValue.C files, but they only restrain the code, and not what i should type in the controlDict file. In addition, I haven't found any single example or tutorial about fieldValue nor fieldValueDelta.

In summarise, I need some advise about the fieldValue function or an example that i could take as model.
I hope you might help me.

Thanks in advance.

Pelayo

[alexeym]

Hi,

Did you look into $FOAM_SRC/postProcessing/functionObjects/field/fieldValues/controlDict? fieldValue is really just a base class with two children: faceSource and cellSource (so examples of fieldValue usage are in faceSource.H and cellSource.H).

[Hamed1117]

hi,
it may help you !
.
.
.
*********************************//
startFrom latestTime;

startTime 0;

stopAt endTime;

endTime 500;

deltaT 1;

writeControl timeStep;

writeInterval 50;

purgeWrite 0;

writeFormat ascii;

writePrecision 6;

writeCompression off;

timeFormat general;

timePrecision 6;

runTimeModifiable true;

functions
{
patch-weighted-area-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 true;

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

// if patch or faceZone: name of patch or faceZone
sourceName outlet;

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

surfaceFormat null;

fields
(
p
phi // surface fields not supported for sampledSurface
U
);
}

}

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