Description🔗

The reference function object computes a field whose values are offset to a reference value obtained by sampling the field at a user-specified location.

The field values are calculated using:

\[\text{ref}_c = s(f_{c}(t) - f_p + f_{off})\]

where:

\(\text{ref}_c\)

Field values at cell

\(s\)

Optional scale factor (default = 1)

\(f_{c}(t)\)

Current field values at cell at this time

\(f_p\)

Field value at position

\(f_{off}\)

Offset field value (default = 0)

Operands🔗

where <Type>=Scalar/Vector/SphericalTensor/SymmTensor/Tensor.

Usage🔗

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

reference1
{
    // Mandatory entries (unmodifiable)
    type            reference;
    libs            (fieldFunctionObjects);

    // Mandatory (inherited) entries (runtime modifiable)
    field           <inpField>;

    // Optional entries (runtime modifiable)
    position    (0 0 0);
    scale       1.0;
    offset      0.0;
    interpolationScheme    cell;

    // Optional (inherited) entries
    result          <fieldResult>;
    region          region0;
    enabled         true;
    log             true;
    timeStart       0;
    timeEnd         1000;
    executeControl  timeStep;
    executeInterval 1;
    writeControl    timeStep;
    writeInterval   1;
}

where the entries mean:

The inherited entries are elaborated in:

• functionObject
• fieldExpression

Example by using the postProcess utility:

postProcess -func "reference(<field>)"

Further information🔗

Tutorial:

• $FOAM_TUTORIALS/incompressible/pisoFoam/RAS/cavity

Source code:

• $FOAM_SRC/functionObjects/field/reference

API:

• Foam::functionObjects::reference

History:

• Introduced in version v1806