flowType

Table of Contents

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:

Example by using the postProcess utility: 

postProcess -func flowType

Further information

Tutorial:

Source code:

History

  • Introduced in version v1606+