• The atmPlantCanopyUSource applies sources on velocity, i.e. U, to incorporate effects of plant canopy for atmospheric boundary layer modelling.
  • The atmPlantCanopyUSource can be applied on any RAS turbulence model.
  • The atmPlantCanopyUSource inherits the traits of the fvOption, and cellSetOption.

Corrections applied to:

U                | Velocity                               [m/s]

Required fields:

U                | Velocity                               [m/s]
plantCd          | Plant canopy drag coefficient          [-]
leafAreaDensity  | Leaf area density                      [1/m]

Model equations

The model expression ([69], Eq. 42):

\[ S_p -= \alpha \rho \left( C_d {LAD} |\u_o| \right) \u \]


\( f_M \) = fvMatrix of the velocity field
\( C_d \) = Plant canopy drag coefficient [-]
\( {LAD} \) = Leaf area density [1/m]
\( \u_o \) = Previous-iteration velocity field [m/s]
\( \alpha \) = Phase fraction in multiphase computations, otherwise equals to 1
\( \rho \) = Fluid density in compressible computations, otherwise equals to 1


Example of the fvOptions specification using constant/fvOptions file:

    // Mandatory entries (unmodifiable)
    type                  atmPlantCanopyUSource;

        // Mandatory (inherited) entries (unmodifiable)
        selectionMode    all;

        // Optional entries (unmodifiable)
        rho             rho;

    // Optional (inherited) entries

where the entries mean:

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

The inherited entries are elaborated in:

Further information


Source code


  • Introduced in version v2006