The fieldValueDelta function object computes a selected operation between two fieldValue function objects.

The operation is applied to all results of each fieldValue object. Accordingly, each object must generate the same number and type of results.


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

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

    // Mandatory entries (runtime modifiable)
    operation       subtract;

    // Optional (inherited) entries
    writeFields       false;
    scalingFactor     1.0;
    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: fieldValueDelta word yes -
libs Library name: fieldFunctionObjects word yes -
operation Operation type to apply to values word yes -
region1 Region1 properties dict yes -
region2 Region2 properties dict yes -

Options for the operation entry:

add           | add
subtract      | subtract
min           | minimum
max           | maximum
average       | average

The inherited entries are elaborated in:

Usage by the postProcess utility is not available.

Further information

Source code:

  • Foam::functionObjects::fieldValueDelta


  • Introduced in version v1606+