Description🔗

The atmNutWallFunction is a boundary condition that provides a wall constraint on the turbulent viscosity (i.e. nut) based on the turbulent kinetic energy (i.e. k) and velocity (i.e. U) for atmospheric boundary layer modelling.

The governing equation of the boundary condition:

\[\tau_w = {U^*_u} {U^*_k}\]

with:

\[{U^*_u} = \frac{\kappa U_w}{ln(z_p / z_0)}\] \[{U^*_k} = C_{\mu}^{1/4} \sqrt{k}\]

where:

References

• Theoretical expressions (tags:RH, SBJM, SM):

  Richards, P. J., & Hoxey, R. P. (1993). Appropriate boundary conditions for computational wind engineering models using the k-ε turbulence model. In Computational Wind Engineering 1 (pp. 145-153). DOI:10.1016/B978-0-444-81688-7.50018-8

  Sørensen, N. N., Bechmann, A., Johansen, J., Myllerup, L., Botha, P., Vinther, S., & Nielsen, B. S. (2007). Identification of severe wind conditions using a Reynolds Averaged Navier-Stokes solver. In Journal of Physics: Conference series (Vol. 75, No. 1, p. 012053). DOI:10.1088/1742-6596/75/1/012053

  Sumner, J., & Masson, C. (2012). k−ε simulations of the neutral atmospheric boundary layer: analysis and correction of discretization errors on practical grids. International journal for numerical methods in fluids, 70(6), 724-741. DOI:10.1002/fld.2709

Usage🔗

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

Boundary file🔗

<patchName>
{
    type            patch;
    ...
}

Field file🔗

<patchName>
{
    // Mandatory entries
    type            atmNutWallFunction;
    z0Min           <scalar>;
    z0              <PatchFunction1<scalar>>;

    // Inherited entries
    ...
}

where:

The inherited entries are elaborated in:

• nutkWallFunctionFvPatchScalarField.H
• PatchFunction1.H

Further information🔗

Tutorial:

• N/A

Source code:

• $FOAM_SRC/atmosphericModels/derivedFvPatchFields/wallFunctions/atmNutWallFunction

API:

• Foam::atmNutWallFunctionFvPatchScalarField

History:

• Introduced in version v2006