continuityError

Table of Contents

Description

The continuityError function object computes local, global and cumulative continuity errors for a flux field.

Local continuity error, \(\epsilon_\text{local}\):

\[ \epsilon_\text{local} = \Delta_t \langle |x| \rangle \]

Global continuity error, \(\epsilon_\text{global}\):

\[ \epsilon_\text{global} = \Delta_t \langle |x| \rangle \]

Cumulative continuity, \(\epsilon_\text{cum}\):

\[ \epsilon_\text{cum} += \epsilon_\text{global} \]

where

\( \Delta_t \) = Time-step size
\( <.> \) = Cell-volume weighted average operator
\( x \) = \( \nabla \cdot \phi \)
\( \phi \) = Flux field

Operands

Operand Type Location
input - -
output file dat $FOAM_CASE/postProcessing/<FO>/<time>/<file>
output field - -

Usage

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

continuityError1
{
    // Mandatory entries (unmodifiable)
    type            continuityError;
    libs            (fieldFunctionObjects);

    // Optional entries (runtime modifiable)
    phi             phi;

    // Optional (inherited) entries
    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: continuityError word yes -
libs Library name: fieldFunctionObjects word yes -
phi Name of flux field word no phi

The inherited entries are elaborated in:

Example by using the postProcess -func utility: 

postProcess -func "continuityError(<field1>, <field2>, ..., <fieldN>)"

Further information

Tutorial:

Source code:

History

  • Introduced in version v1906