Properties

The pressure drop across the cellZone is evaluated according to the options:

constant: user-specified $ \Delta p $ [Pa]
volumetricFlowRateTable: $ \Delta p $ is read as a table from file
DarcyForchheimer: $ \Delta p = (D + 0.5 \rho |U| I ) |U| L $ [Pa] where D, I and L are user inputs.

Note

the cellZone should describe a set of cells with a 1-cell thickness in the flow direction
the source requires the set of faces upstream of the cellZone to be specified as a faceZone

A sample result is shown below, where the effect of flow deflection across the cellZone is clearly evident.

Deflection example

Usage

The option is specified using:

registerOrientation
{
    type&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;    directionalPressureGradientExplicitSource;
    active&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;    true;
    selectionMode&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;cellZone;
    cellZone&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;c1Zone;
    fieldNames&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(U);
    flowDir&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(1&nbsp;2&nbsp;0);&nbsp;&nbsp;&nbsp;&nbsp;//&nbsp;new&nbsp;flow&nbsp;direction&nbsp;in&nbsp;the&nbsp;general&nbsp;coordinate&nbsp;system
    relaxationFactor&nbsp;&nbsp;&nbsp;&nbsp;0.3;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;//&nbsp;relax&nbsp;the&nbsp;application&nbsp;of&nbsp;the&nbsp;source&nbsp;term
    faceZone&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;f1Zone;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;//&nbsp;faceZone&nbsp;upstream&nbsp;the&nbsp;cellZone

    //&nbsp;Pressure&nbsp;drop&nbsp;model&nbsp;[Pa]
    model&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;        DarcyForchheimer;&nbsp;&nbsp;&nbsp;//&nbsp;volumetricFlowRateTable | constant

    //&nbsp;DarcyForchheimer
    //&nbsp;deltaP&nbsp;=&nbsp;(D*mu&nbsp;+&nbsp;0.5*rho*magUn)*magUn*length
    D&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;        5e7;
    I&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;        0;
    length&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;        0.01;  // Virtual thickness of the porosity corresponding to the D and I values

    //&nbsp;constant&nbsp;pressure&nbsp;drop&nbsp;model
    //&nbsp;pressureDrop&nbsp;&nbsp;&nbsp;&nbsp;8;

    //&nbsp;volumetricFlowRateTable&nbsp;pressure&nbsp;drop&nbsp;model
    //&nbsp;outOfBounds&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;clamp;
    //&nbsp;file    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;"volFlowRateTable";
}

Further information

Tutorials

$FOAM_TUTORIALS/heatTransfer/chtMultiRegionFoam/windshieldCondensation/system/cabin/fvOptions

Source code

$FOAM_SRC/fvOptions/sources/derived/directionalPressureGradientExplicitSource

Would you like to suggest an improvement to this page?

Create an issue

Licensed under the Creative Commons License BY-NC-ND

Table of Contents

Properties

Usage

Further information