The pressureInletOutletParSlipVelocity 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 slip condition is applied tangential to the patch.


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

Boundary file

    type            patch;

Field file

    // Mandatory entries
    type            pressureInletOutletParSlipVelocity;

    // Optional entries
    phi             <word>;
    rho             <word>;

    // Inherited entries;


Property Description Type Required Default
type Type name: pressureInletOutletParSlipVelocity word yes -
phi Name of flux field word no phi
rho Name of density field word no rho

The inherited entries are elaborated in:

  • Foam::mixedFvPatchField

  • 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 2.1.0