atmNutUWallFunction

Description

The atmNutUWallFunction is a boundary condition that provides a wall constraint on the turbulent viscosity (i.e. nut) based on velocity (i.e. U) for atmospheric boundary layer modelling. It is designed to be used in conjunction with the atmBoundaryLayerInletVelocity boundary condition.

The governing equation of the boundary condition:

$$u = \frac{u^*}{\kappa} ln \left(\frac{z + z_0}{z_0}\right)$$

where:

Property	Description
$u^*$	Friction velocity
$\kappa$	von Karman constant
$z_0$	Surface roughness length [m]
$z$	Ground-normal coordinate

Usage

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

Boundary file

<patchName>
{
    type            patch;
    ...
}

Field file

<patchName>
{
    // Mandatory entries
    type            atmNutUWallFunction;
    z0              <PatchFunction1<scalar>>;

    // Optional entries
    boundNut        <bool>;

    // Inherited entries
    ...
}

where:

Property	Description	Type	Required	Default
type	Type name: atmNutUWallFunction	word	yes	-
z0	Surface roughness length [m]	PatchFunction1<scalar>	yes	-
boundNut	Flag to zero-bound nut near wall	bool	no	false

The inherited entries are elaborated in:

• nutUWallFunctionFvPatchScalarField.H
• PatchFunction1.H

Further information

Tutorial:

• N/A

Source code:

• atmNutUWallFunction

API:

• Foam::atmNutUWallFunctionFvPatchScalarField

History: Introduced in version v2006