OpenFOAM Documentation - atmPlantCanopyTurbSource

Properties🔗

The atmPlantCanopyTurbSource applies sources on either epsilon or omega to incorporate effects of plant canopy for atmospheric boundary layer modelling.
The atmPlantCanopyTurbSource can be applied on epsilon or omega based RAS turbulence models.
The atmPlantCanopyTurbSource inherits the traits of the fvOption, and cellSetOption.

Corrections applied to either of the below, if exist:

epsilon: Turbulent kinetic energy dissipation rate [m$^2$/s$^3$]
omega: Specific dissipation rate [1/s]

Required fields:

epsilon/omega: Dissipation rate OR Spec. dissipation rate [m$^2$/s$^3$]/[1/s]
plantCd: Plant canopy drag coefficient [-]
leafAreaDensity: Leaf area density [1/m]

Model equations🔗

Turbulent kinetic energy dissipation rate🔗

The model expression for epsilon:

\[S_p -= \alpha \rho \left( C_1 - C_2 \right) C_{canopy} \epsilon\]

with ([65], Eq. 42):

\[C_{canopy} = 12.0 \sqrt{C_\mu} C_d {LAD} |\u_o|\]

Specific dissipation rate🔗

The model expression for omega:

\[S_p -= \alpha \rho \left( \gamma - \beta \right) C_{canopy} \omega\]

Where:

$S_p$: Source term without boundary conditions
$C_1$: Model constant (epsilon-based models) [-]
$C_2$: Model constant (epsilon-based models) [-]
$C_\mu$: Empirical model constant [-]
$\beta$: Model constant (omega-based models) [-]
$\gamma$: Model constant (omega-based models) [-]
$\epsilon$: Turbulent kinetic energy dissipation rate (Current iteration) [m2/s3]
$\omega$: Specific dissipation rate (Current iteration) [1/s]
$C_d$: Plant canopy drag coefficient [-]
${LAD}$: Leaf area density [1/m]
$\u_o$: Previous-iteration velocity field [m/s]
$C_{canopy}$: Plant canopy term
$\alpha$: Phase fraction in multiphase computations, otherwise equals to 1
$\rho$: Fluid density in compressible computations, otherwise equals to 1

Usage🔗

Example of the fvOptions specification using constant/fvOptions file:

atmPlantCanopyTurbSource1
{
    // Mandatory entries (unmodifiable)
    type                  atmPlantCanopyTurbSource;

    atmPlantCanopyTurbSourceCoeffs
    {
        // 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: atmPlantCanopyTurbSource	word	yes	-
rho	Name of density field	word	no	rho

The inherited entries are elaborated in:

fvOption
- cellSetOption

Further information🔗

Tutorials

Source code

$FOAM_SRC/atmosphericModels/fvOptions/atmPlantCanopyTurbSource

History:

Introduced in version v2006

Open∇FOAM

atmPlantCanopyTurbSource