nutkWallFunction
boundary condition provides a wall constraint on the turbulent viscosity, i.e. nut
, based on the turbulent kinetic energy, i.e. k
, for low- and high-Reynolds number turbulence models.nutkWallFunction
condition inherits the traits of the nutWallFunction boundary condition.Required fields:
nut | Turbulent viscosity [m2/s]
The model expressions:
\[ \nu_t = f_{blend}(\nu_{t_{vis}}, \nu_{t_{log}}) \]
with
\[ \nu_{t_{vis}} = 0 \]
\[ \nu_{t_{log}} = \nu_w \left( \frac{y^+ \kappa}{\ln(E y^+)} - 1 \right) \]
\[ y^+ = C_\mu^{1/4} y \frac{\sqrt{k}}{\nu_w} \]
where
\( \nu_t \) | = | Turbulent viscosity [m2/s] |
\( \nu_{t_{vis}} \) | = | \(\nu_t\) computed by the viscous sublayer assumptions [m2/s] |
\( \nu_{t_{log}} \) | = | \(\nu_t\) computed by the inertial sublayer assumptions [m2/s] |
\( \nu_w \) | = | Kinematic viscosity of fluid near wall [m2/s] |
\( y^+ \) | = | Estimated wall-normal height of the cell centre in wall units |
\( \kappa \) | = | von Kármán constant [-] |
\( E \) | = | Wall roughness parameter [-] |
\( C_\mu \) | = | Empirical model constant [-] |
\( y \) | = | Wall-normal height [m] |
\( k \) | = | Turbulent kinetic energy [m2/s2] |
\( f_{blend} \) | = | Wall-function blending operator between the viscous and inertial sublayer contributions |
Example of the boundary condition specification:
<patchName> { // Mandatory entries (unmodifiable) type nutkWallFunction; // Optional (inherited) entries ... }
where the entries mean:
Property | Description | Type | Required | Default |
---|---|---|---|---|
type | Type name: nutkWallFunction | word | yes | - |
The inherited entries are elaborated in:
Tutorial
Source code