This class provides functions to evaluate the velocity and turbulence distributions appropriate for atmospheric boundary layers (ABL). More...

Inheritance diagram for atmBoundaryLayer:

[legend]

Public Member Functions
	atmBoundaryLayer ()
	Construct null. More...

	atmBoundaryLayer (const vector &flowDir, const vector &zDir, const scalar Uref, const scalar Zref, const scalarField &z0, const scalarField &zGround, const scalar kappa=kappaDefault_, const scalar Cmu=CmuDefault_, const scalar ULower=0, const scalar kLower=0, const scalar epsilonLower=0)
	Construct from components. More...

	atmBoundaryLayer (const vectorField &p, const dictionary &)
	Construct from the coordinates field and dictionary. More...

	atmBoundaryLayer (const atmBoundaryLayer &, const fvPatchFieldMapper &)
	Construct by mapping given. More...

	atmBoundaryLayer (const atmBoundaryLayer &)
	Copy constructor. More...

const vector &	flowDir () const
	Return flow direction. More...

const vector &	zDir () const
	Return z-direction. More...

const scalarField &	Ustar () const
	Return friction velocity. More...

void	map (const atmBoundaryLayer &, const fvPatchFieldMapper &)
	Map the given atmBoundaryLayer onto this atmBoundaryLayer. More...

void	reset (const atmBoundaryLayer &)
	Reset the atmBoundaryLayer to the given atmBoundaryLayer. More...

tmp< vectorField >	U (const vectorField &p) const
	Return the velocity distribution for the ATM. More...

tmp< scalarField >	k (const vectorField &p) const
	Return the turbulent kinetic energy distribution for the ATM. More...

tmp< scalarField >	epsilon (const vectorField &p) const
	Return the turbulent dissipation rate distribution for the ATM. More...

void	write (Ostream &) const
	Write. More...

Detailed Description

This class provides functions to evaluate the velocity and turbulence distributions appropriate for atmospheric boundary layers (ABL).

The profile is derived from the friction velocity, flow direction and "vertical" direction:

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

$k = \frac{(U^*)^2}{\sqrt{C_mu}}$

$\epsilon = \frac{(U^*)^3}{\kappa(z - z_g + z_0)}$

where

	=	Friction velocity
$\kappa$	=	von Karman's constant
	=	Turbulence viscosity coefficient
	=	Vertical coordinate
	=	Surface roughness height [m]
	=	Minimum z-coordinate [m]

and

$U^* = \kappa\frac{U_{ref}}{ln\left(\frac{Z_{ref} + z_0}{z_0}\right)}$

where

$U_{ref}$	=	Reference velocity at $Z_{ref}$ [m/s]
$Z_{ref}$	=	Reference height [m]

Use in the atmBoundaryLayerInletVelocity, atmBoundaryLayerInletK and atmBoundaryLayerInletEpsilon boundary conditions.

Reference: D.M. Hargreaves and N.G. Wright, "On the use of the k-epsilon model in commercial CFD software to model the neutral atmospheric boundary layer", Journal of Wind Engineering and Industrial Aerodynamics 95(2007), pp 355-369.

Usage

Property	Description	Required	Default
`flowDir`	Flow direction	yes
`zDir`	Vertical direction	yes
`kappa`	von Karman's constant	no	0.41
`Cmu`	Turbulence viscosity coefficient	no	0.09
`Uref`	Reference velocity [m/s]	yes
`Zref`	Reference height [m]	yes
`z0`	Surface roughness height [m]	yes
`zGround`	Minimum z-coordinate [m]	yes
`Ulower`	Velocity below the BL	no
`kLower`	Turbulence k below the BL	no
`epsilonLower`	Turbulence epsilon below the BL	no

Example of the boundary condition specification:

    ground
    {
        type            atmBoundaryLayerInletVelocity;
        flowDir         (1 0 0);
        zDir            (0 0 1);
        Uref            10.0;
        Zref            20.0;
        z0              uniform 0.1;
        zGround         uniform 0.0;
    }

Note: D.M. Hargreaves and N.G. Wright recommend Gamma epsilon in the k-epsilon model should be changed from 1.3 to 1.11 for consistency. The roughness height (Er) is given by Er = 20 z0 following the same reference.

Source files

Definition at line 220 of file atmBoundaryLayer.H.

Constructor & Destructor Documentation

◆ atmBoundaryLayer() [1/5]

atmBoundaryLayer ( )

Construct null.

Definition at line 56 of file atmBoundaryLayer.C.

◆ atmBoundaryLayer() [2/5]

atmBoundaryLayer	(	const vector &	flowDir,
		const vector &	zDir,
		const scalar	Uref,
		const scalar	Zref,
		const scalarField &	z0,
		const scalarField &	zGround,
		const scalar	kappa = `kappaDefault_`,
		const scalar	Cmu = `CmuDefault_`,
		const scalar	ULower = `0`,
		const scalar	kLower = `0`,
		const scalar	epsilonLower = `0`
	)