atmLengthScaleTurbSource
applies sources on either epsilon
or omega
to correct mixing-length scale estimations for atmospheric boundary layer modelling.atmLengthScaleTurbSource
can be applied on epsilon
or omega
based RAS turbulence models.atmLengthScaleTurbSource
inherits the traits of the fvOption, and cellSetOption
.Corrections applied to either of the below, if exist:
epsilon | Turbulent kinetic energy dissipation rate [m2/s3] omega | Specific dissipation rate [1/s]
Required fields, either of the below:
epsilon | Turbulent kinetic energy dissipation rate [m2/s3] omega | Specific dissipation rate [1/s]
The model expression for epsilon
:
\[ S_p = \alpha \rho C_1^* \frac{G_o}{\nu} C_\mu k_o \]
with ([3], Eq. 16 wherein the exponentiation n
is not present. n
is an ad-hoc implementation):
\[ C_1^* = (C_2 - C_1) \left( \frac{L}{L_{max}} \right)^n \]
Mixing-length scale estimation ([61], Eq. 10.37 & p. 374):
\[ L = C_\mu^{3/4} \frac{k_o^{3/2}}{\epsilon_o} \]
The model expression for omega
:
\[ S_p = \alpha \rho \gamma^* \frac{G_o}{\nu} \]
with ([36], Eq. 3.34):
\[ \gamma^* = \left( \gamma - \beta \right) \left( \frac{L}{L_{max}} \right)^n \]
Mixing-length scale estimation ([36], Eq. 3.20):
\[ L = \frac{\sqrt{k}}{C_\mu^{1/4} \omega_o} \]
where
\( S_p \) | = | Source term without boundary conditions |
\( \epsilon_o \) | = | Previous-iteration epsilon [m2/s3] |
\( \omega_o \) | = | Previous-iteration omega [1/s] |
\( k_o \) | = | Previous-iteration k [m2/s2] |
\( G_o \) | = | Previous-iteration k-production contribution [m2/s3] |
\( C_1 \) | = | Model constant (epsilon-based models) [-] |
\( C_2 \) | = | Model constant (epsilon-based models) [-] |
\( C_1^* \) | = | Modified model constant field (epsilon-based models) [-] |
\( C_\mu \) | = | Empirical model constant [-] |
\( \gamma \) | = | Model constant (omega-based models) [-] |
\( \beta \) | = | Model constant (omega-based models) [-] |
\( \gamma^* \) | = | Modified model constant field (omega-based models) [-] |
\( \nu \) | = | Kinematic viscosity of fluid [m2/s] |
\( L \) | = | Mixing-length scale [m] |
\( L_{max} \) | = | Maximum mixing-length scale [m] |
\( \alpha \) | = | Phase fraction in multiphase computations, otherwise equals to 1 |
\( \rho \) | = | Fluid density in compressible computations, otherwise equals to 1 |
Example of the fvOptions specification using constant/fvOptions
file:
atmLengthScaleTurbSource1 { // Mandatory entries (unmodifiable) type atmLengthScaleTurbSource; atmLengthScaleTurbSourceCoeffs { // Mandatory (inherited) entries (unmodifiable) selectionMode all; // Optional entries (unmodifiable) rho rho; Lmax 41.575; n 3.0; } // Optional (inherited) entries ... }
where the entries mean:
Property | Description | Type | Required | Default |
---|---|---|---|---|
type | Type name: atmLengthScaleTurbSource | word | yes | - |
rho | Name of density field | word | no | rho |
Lmax | Maximum mixing-length scale | scalar | no | 41.575 |
n | Mixing-length scale exponent | scalar | no | 3.0 |
The inherited entries are elaborated in:
cellSetOption
Tutorials
Source code
History