The semiPermeableBaffleVelocity is a boundary condition that provides a velocity boundary condition for baffles which are permeable to a some species and impermeable to others. It must be used in conjunction with the corresponding mass-fraction condition, semiPermeableBaffleMassFraction.

This condition sums the species fluxes generated by the the mass-fraction conditions, and uses this total to set the velocity.


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

Boundary file

    type            patch;

Field file

    // Mandatory entries
    type            semiPermeableBaffleVelocity;

    // Optional entries
    rho             <word>;

    // Inherited entries


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

The inherited entries are elaborated in:

  • mappedPatchBase.H
  • fixedValueFvPatchField.H

Further information


Source code:



  • Introduced in version v2206