The pressureInletOutletVelocity is a velocity inlet/outlet boundary condition that applies a zero-gradient condition for outflow (as defined by the flux); and obtains velocity from the flux with specified inlet direction.

The tangential patch velocity can be optionally specified.


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

Boundary file

    type            patch;

Field file

    // Mandatory entries
    type            pressureInletOutletVelocity;

    // Optional entries
    tangentialVelocity  <vectorField>;
    phi             <word>;

    // Inherited entries;


Property Description Type Required Default
type Type name: pressureInletOutletVelocity word yes -
tangentialVelocity Tangential velocity field vectorField no Zero
phi Name of flux field word no phi

The inherited entries are elaborated in:

  • Foam::directionMixedFvPatchField

  • Sign conventions:

    • positive flux (out of domain): apply zero-gradient condition
    • negative flux (into of domain): derive from the flux with specified direction

Further information


Source code:



  • Introduced in version 1.5