Properties🔗
- One equation model based on a modified turbulence viscosity, \(\tilde{\nu}\)
Model equations🔗
The \(\tilde{\nu}\) transport equation is given by:
\[\Ddt{\rho \tilde{\nu}} = \div \left( \rho D_\tilde{\nu} \tilde{\nu} \right) + \frac{C_{b2}}{\sigma_{\nu_t}} \rho \mag{\grad \tilde{\nu}}^2 + C_{b1} \rho \tilde{S} \tilde{\nu} \left(1 - f_{t2}\right) - \left(C_{w1} f_w - \frac{C_{b1}}{\kappa^2} f_{t2}\right) \rho \frac{\tilde{\nu}^2}{\tilde{d}^2} + S_\tilde{\nu}\]where the length scale \(\tilde{d}\) is defined by:
\[\tilde{d} = \min \left( \Psi C_{DES} \Delta, y \right)\]and \(\Psi\) is the low Reynolds number correction function:
\[\Psi^2 = \min \left[ 10^2, \frac{1 - \frac{1 - C_{b1}}{C_{w1} \kappa^2 f_w^{*}} \left[ f_{t2} + \left(1 - f_{t2}\right) f_{v2} \right]}{f_{v1} \max \left(10^{-10}, 1-f_{t2} \right)} \right]\]Default model coefficients🔗
\(\sigma_{\nu_t}\) | \(C_{b1}\) | \(C_{b2}\) | \(C_{w1}\) | \(C_{w2}\) | \(C_{w3}\) |
---|---|---|---|---|---|
2/3 | 0.1355 | 0.622 | \(\frac{C_{b1}}{\kappa^2} + \frac{1 + C_{b2}}{\sigma_{\nu_t}}\) | 0.3 | 2 |
\(C_{v1}\) | \(C_{s}\) | \(C_{\mathit{DES}}\) | \(C_{k}\) | \(C_{t3}\) | \(C_{t4}\) | \(f_w^{*}\) |
---|---|---|---|---|---|---|
7.1 | 0.3 | 0.65 | 0.07 | 1.2 | 0.5 | 0.424 |
Initialisation🔗
Usage🔗
The model is specified using:
LES
{
turbulence on;
LESModel SpalartAllmarasDES;
// Optional entries
SpalartAllmarasDESCoeffs
{
// Apply low-Reynolds number correction; default = yes
lowReCorrection yes;
}
}
Boundary conditions🔗
Inlet
Outlet
Walls
- wall functions
Further information🔗
Source code:
References: