flowType

Description

The flowType function object computes the flow type indicator of an input velocity field.

The flow type indicator is obtained according to the following equation:

$$\lambda = \frac{\mag{\tensor D} - \mag{\tensor \Omega}}{ \mag{\tensor D} + \mag{\tensor \Omega}}$$

where

$\lambda$ : Flow type indicator

$\tensor D$ : Symmetric part of the gradient tensor of velocity

$\tensor \Omega$ : Skew-symmetric part of the gradient tensor of velocity

The flow type indicator values mean:

-1 : rotational flow

0 : simple shear flow

1 : planar extensional flow

Operands

Operand	Type	Location
input	volVectorField	$FOAM_CASE/<time>/<inpField>
output file	-	-
output field	volScalarField	$FOAM_CASE/<time>/<outField>

Usage

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

flowType1
{
    // Mandatory entries (unmodifiable)
    type            flowType;
    libs            (fieldFunctionObjects);

    // Optional (inherited) entries
    field           <field>;
    result          <fieldResult>;
    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: flowType	word	yes	-
libs	Library name: fieldFunctionObjects	word	yes	-

The inherited entries are elaborated in:

• functionObject
• fieldExpression

Example by using the postProcess utility:

postProcess -func flowType

Further information

Tutorial:

• cavity

Source code:

• flowType

API:

• Foam::functionObjects::flowType

History: Introduced in version v1606+