continuityError

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:

• functionObject
• writeFile

Example by using the postProcess -func utility:

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

Stored properties

Reduced data

The following data are stored by the function object, and can be used by other function objects:

• local : local continuity error
• global : global continuity error
• cumulative : cumulative continuity error

Further information

Tutorial:

• cavity

Source code:

• continuityError

API:

• Foam::functionObjects::continuityError

History: Introduced in version v1906