fieldCoordinateSystemTransform

Description

The fieldCoordinateSystemTransform function object is used to convert a field from the global Cartesian system to a local user-specified co-ordinate system.

Operands

Operand	Type	Location
input	{vol,surface}<Type>Field(s)	$FOAM_CASE/<time>/<inpField>s
output file	-	-
output field	{vol,surface}<Type>Field(s)	$FOAM_CASE/<time>/<outField>s

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

Usage

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

To transform the global velocity into a local cylindrical system defined by

origin: (0 0 0)
axis:   (0 0 1)
radius: (1 0 0)

the following entries may be used:

transform1
{
    // Mandatory entries (unmodifiable)
    type            fieldCoordinateSystemTransform;
    libs            (fieldFunctionObjects);

    // Mandatory entries (runtime modifiable)
    fields          (U);
    coordinateSystem
    {
        origin          (0 0 0);
        coordinateRotation
        {
            type            axesRotation;
            e3              (0 0 1);
            e1              (1 0 0);
        }
    }

    // Optional (inherited) entries
    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: fieldCoordinateSystemTransform	word	yes	-
libs	Library name: fieldFunctionObjects	word	yes	-
fields	Names of the operand fields	wordList	yes	-
coordinateSystem	Local coordinate system	dict	yes	-

The inherited entries are elaborated in:

• functionObject

Usage by the postProcess utility is not available.

Stored properties

Fields

Each input field is transformed into a field with the name:

<field>:Transformed

For the example above, the U field is transformed into

U:Transformed

which is registered to the mesh database and written to the time directories according to the writeControl entry.

Further information

Tutorial:

• pipeCyclic

Source code:

• fieldCoordinateSystemTransform

API:

• Foam::functionObjects::fieldCoordinateSystemTransform

History: Introduced in version v1606+