Description🔗

The variableHeightFlowRate is a boundary condition that provides a phase fraction condition based on the local flow conditions, whereby the values are constrained to lay between user-specified upper and lower bounds.

The behaviour is described by:

• if alpha > upperBound:
  • apply a fixed value condition, with a uniform level of the upper bound
• if lower bound <= alpha <= upper bound:
  • apply a zero-gradient condition
• if alpha < lowerBound:
  • apply a fixed value condition, with a uniform level of the lower bound

Usage🔗

The condition requires entries in both the boundary and field files.

Boundary file🔗

<patchName>
{
    type            patch;
    ...
}

Field file🔗

<patchName>
{
    // Mandatory entries
    type            variableHeightFlowRate;
    lowerBound      <scalar>;
    upperBound      <scalar>;

    // Optional entries
    phi             <word>;

    // Inherited entries
    ...
}

where:

The inherited entries are elaborated in:

• mixedFvPatchFields.H

Further information🔗

Tutorial:

• $FOAM_TUTORIALS/multiphase/interFoam/RAS/weirOverflow

Source code:

• $FOAM_SRC/finiteVolume/fields/fvPatchFields/derived/variableHeightFlowRate

API:

• Foam::variableHeightFlowRateFvPatchField

History:

• Introduced in version 2.1.1