The filmHeightInletVelocity is boundary condition designed to be used in conjunction with surface film modelling. It provides a velocity inlet boundary condition for patches where the film height is specified. The inflow velocity is obtained from the flux with a direction normal to the patch faces using:

\[\u_p = \frac{\vec{n} \phi}{\rho |\vec{S}_f| \delta}\]


Property Description
\(\u_p\) Patch velocity [m/s]
\(\vec{n}\) Patch normal vector
\(\phi\) Mass flux [kg/s]
\(\rho\) Density [kg/m^3]
\(\vec{S}_f\) Patch face area vectors [m^2]
\(\delta\) Film height [m]


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

Boundary file

    type            wall;

Field file

    // Mandatory entries
    type            filmHeightInletVelocity;

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

    // Inherited entries


Property Description Type Required Default
type Type name: filmHeightInletVelocity word yes -
phi Name of flux field word yes -
rho Name of density field word yes -
deltaf Name of height field word yes -

The inherited entries are elaborated in:

  • fixedValueFvPatchField.H

Further information


  • N/A

Source code:



  • Introduced in version 2.0.0