The supersonicFreestream is a boundary condition that provides a supersonic free-stream condition.

  • supersonic inflow is assumed to occur according to the Prandtl-Meyer expansion process.
  • subsonic outflow is applied via a zero-gradient condition from inside the domain.


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

Boundary file

    type            patch;

Field file

    // Mandatory entries
    type            supersonicFreestream;
    UInf            <vector>;
    pInf            <scalar>;
    TInf            <scalar>;
    gamma           <scalar>;

    // Optional entries
    T               <word>;
    p               <word>;
    psi             <word>;

    // Inherited entries;


Property Description Type Required Default
type Type name: supersonicFreestream word yes -
UInf Freestream velocity vector yes -
pInf Freestream pressure vector yes -
TInf Freestream temperature vector yes -
gamma Heat capacity ratio scalar yes -
T Name of temperature field word no T
p Name of pressure field word no p
psi Name of compressibility field word no thermo:psi

The inherited entries are elaborated in:

Further information


Source code:



  • Introduced in version 1.5