The fluxSummary function object computes the volumetric- or mass-flux information across selections of face zones.

Statistics include:

  • positive flux:
\[\phi_{+} = \sum \phi_{>0}\]
  • negative flux:
\[\phi_{-} = \sum \phi_{<0}\]
  • net flux:
\[\phi_{\mathrm{net}} = \sum \phi\]
  • absolute flux:
\[\phi_{\mathrm{abs}} = \sum |{\phi}|\]


Operand Type Location
input - -
output file dat $FOAM_CASE/postProcessing/<FO>/<time>/<faceN>
output field - -


Example of the fluxSummary function object by using functions sub-dictionary in system/controlDict file:

    // Mandatory entries (unmodifiable)
    type            fluxSummary;
    libs            (fieldFunctionObjects);

    // Mandatory entries (runtime modifiable)
    mode            cellZoneAndDirection;
        (porosity (1 0 0))

    // Optional entries  (runtime modifiable)
    phi             phi;
    scaleFactor     1.0;
    tolerance       0.8;

    // Optional (inherited) entries
    writePrecision  8;
    writeToFile     true;
    useUserTime     true;
    region          region0;
    enabled         true;
    log             true;
    timeStart       0;
    timeEnd         1000;
    executeControl  timeStep;
    executeInterval 1;
    writeControl    timeStep;
    writeInterval   1;

where the entries mean:

Property Description Type Required Default
type Type name: fluxSummary word yes -
libs Library name: fieldFunctionObjects word yes -
mode Mode to generate faces to test word yes -
phi Name of surface flux field word no phi
scaleFactor Factor to scale results scalar no 1.0
tolerance Tolerance for reference direction scalar no 0.8

Options for the mode entry:

faceZoneAndDirection | faceZone with prescribed positive direction
cellZoneAndDirection | cellZone with prescribed positive direction

The inherited entries are elaborated in:

Usage by the postProcess utility is not available.

Notes on entries

  • For surface and direction, phi=U can be used for determining the fluxes.
  • In case of mode=cellZoneAndDirection, faces bounding the cellZone are extracted and processed.

Further information


Source code: