atmBoundaryLayerInletEpsilon

Table of Contents

Properties

  • The atmBoundaryLayerInletEpsilon boundary condition provides a generalised log-law type ground-normal inlet boundary condition for the turbulent kinetic energy dissipation rate, i.e. epsilon, for homogeneous, two-dimensional, dry-air, equilibrium and neutral atmospheric boundary layer modelling.
  • The atmBoundaryLayerInletEpsilon boundary condition inherits the traits of the atmBoundaryLayer, and inletOutlet.

Model equations

The ground-normal turbulent kinetic energy dissipation rate profile expression, i.e. epsilon (([99], Eq. 22), ([63], Eq. 8), ([24], Eq. 7 when C1=0 and C2=1)):

\[ \epsilon = \frac{(u^*)^3}{\kappa (z - d + z_0)} \sqrt{C_1 \ln \left( \frac{z - d + z_0}{z_0} \right) + C_2} \]

where

\( \epsilon \) = Ground-normal turbulent kinetic energy dissipation rate profile [m2/s3]
\( u^* \) = Friction velocity [m/s]
\( \kappa \) = von Kármán constant [-]
\( z \) = Ground-normal coordinate component [m]
\( z_0 \) = Aerodynamic roughness length [m]
\( d \) = Ground-normal displacement height [m]
\( C_1 \) = Curve-fitting coefficient for [99] profiles [-]
\( C_2 \) = Curve-fitting coefficient for [99] profiles [-]

Usage

Example of the boundary condition specification: 

inlet
{
    // Mandatory entries (unmodifiable)
    type            atmBoundaryLayerInletEpsilon;

    // Mandatory (inherited) entries (runtime modifiable)
    flowDir         (1 0 0);
    zDir            (0 0 1);
    Uref            10.0;
    Zref            0.0;
    z0              uniform 0.1;
    d               uniform 0.0;

    // Optional (inherited) entries (unmodifiable)
    kappa           0.41;
    Cmu             0.09;
    initABL         true;
    phi             phi;
    C1              0.0;
    C2              1.0;

    // Conditional mandatory (inherited) entries (runtime modifiable)
    value           uniform 0;    // when initABL=false
}

where the entries mean:

Property Description Type Required Default
type Type name: atmBoundaryLayerInletEpsilon word yes -

The inherited entries are elaborated in:

Further information

Tutorial:

Source code:

History

  • Introduced in version 1.7.0