fieldExplicitPorositySource

Syntax

Defined in an fvOptions dictionary in the system folder of the CFD case. Can only be applied if the solver is able to handle fvOptions.

  • selectionMode = selection mode (all or cellZoneSet)

  • solidFractionName = name of the solidfraction field to use (default: “solidFraction”)

  • voidFractionName = name of the voidfraction field to use. Mutually exclusive with solidFractionName. If used, solidfraction = 1 - voidfraction. (default: “undefined”)

  • compressibleCase = Switch to set if case is compressbile or not. Affects only internal unit conversions. (default: true)

  • lowerSolidFractionThreshold = lower value for solidfraction field when deciding if to apply the porosity term, i.e. no porosity for solidfraction < lowerSolidFractionThreshold (default: 0)

  • upperSolidFractionThreshold = upper value for solidfraction field when deciding if to apply the porosity term, i.e. full porosity for solidfraction > upperSolidFractionThreshold (default: 1)

Examples

porosity
{
    type            fieldExplicitPorositySource;
    solidFractionName "C";
    active          yes;
    fieldExplicitPorositySourceCoeffs
    {
        seletionMode    all;
        type            DarcyForchheimer;

        d   (7e5 7e5 7e5);
        f   (0 0 0);

        coordinateSystem
        {
            type    cartesian;
            origin  (0 0 0);
            coordinateRotation
            {
                type    axesRotation;
                e1      (1 0 0);
                e3      (0 0 1);
            }
        }
    }
}

Description

This model can be used to add an additional porosity to the flow equations. The model is a derivative of explicitPorositySource from OpenFOAM with an additional marker field termed solidFractionName. If the solidFraction field is 0, no porosity term is applied. If the field is 1 the full porosity term is applied.

Using lowerSolidFractionThreshold and upperSolidFractionThreshold this range can be altered such that the additional porosity is not applied for solidfraction < lowerSolidFractionThreshold and fully applied for solidfraction > upperSolidFractionThreshold. The impact of the porosity term is scaled linearly between lowerSolidFractionThreshold and upperSolidFractionThreshold.

By default, the solid fraction is used. Alternatively, a void fraction can be used to trigger the porosity term. The latter is always used when voidFractionName is set.

Restrictions

This model should not be used with the keyword voidFractionName in a CFDEM solver.