The inletOutlet is a generic boundary condition that provides an outflow condition, with specified inflow for the case of return flow.


The condition requires entries in both theboundary` and field files.

Boundary file

    type            patch;

Field file

    // Mandatory entries
    type            inletOutlet;
    inletValue      <Field<Type>>;

    // Optional entries
    phi             <word>;

    // Inherited entries;


Property Description Type Required Default
type Type name: inletOutlet word yes -
inletValue Patch field for reverse flow Field<Type> yes -
phi Name of flux field word no phi

The inherited entries are elaborated in:

  • Foam::mixedFvPatchField

  • The mode of operation is determined by the sign of the flux across the patch faces.
  • Sign conventions:
    • Positive flux (out of domain): apply zero-gradient condition.
    • Negative flux (into domain): apply the inletValue fixed-value.

Further information


Source code:



  • Introduced in version 1.5