k–omega turbulence model
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In computational fluid dynamics, the k–omega (k–ω) turbulence model is a common two-equation turbulence model, that is used as an approximation for the Reynolds-averaged Navier–Stokes equations (RANS equations). The model attempts to predict turbulence by two partial differential equations for two variables, k and ω, with the first variable being the turbulence kinetic energy (k) while the second (ω) is the specific rate of dissipation (of the turbulence kinetic energy k into internal thermal energy).
Standard (Wilcox) k–ω turbulence model
[edit]The eddy viscosity νT, as needed in the RANS equations, is given by: νT = k/ω, while the evolution of k and ω is modelled as:[1]
![{\displaystyle {\begin{aligned}&{\frac {\partial (\rho k)}{\partial t}}+{\frac {\partial (\rho u_{j}k)}{\partial x_{j}}}=\rho P-\beta ^{*}\rho \omega k+{\frac {\partial }{\partial x_{j}}}\left[\left(\mu +\sigma _{k}{\frac {\rho k}{\omega }}\right){\frac {\partial k}{\partial x_{j}}}\right],\qquad {\text{with }}P=\tau _{ij}{\frac {\partial u_{i}}{\partial x_{j}}},\\&\displaystyle {\frac {\partial (\rho \omega )}{\partial t}}+{\frac {\partial (\rho u_{j}\omega )}{\partial x_{j}}}={\frac {\alpha \omega }{k}}\rho P-\beta \rho \omega ^{2}+{\frac {\partial }{\partial x_{j}}}\left[\left(\mu +\sigma _{\omega }{\frac {\rho k}{\omega }}\right){\frac {\partial \omega }{\partial x_{j}}}\right]+{\frac {\rho \sigma _{d}}{\omega }}{\frac {\partial k}{\partial x_{j}}}{\frac {\partial \omega }{\partial x_{j}}}.\end{aligned}}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/6375759ced29685aacda87b592c941d8851741f4)
For recommendations for the values of the different parameters, see Wilcox (2008).
Notes
[edit]References
[edit]- Wilcox, D. C. (2008), "Formulation of the k–ω Turbulence Model Revisited", AIAA Journal, 46 (11): 2823–2838, Bibcode:2008AIAAJ..46.2823W, doi:10.2514/1.36541
- Wilcox, D. C. (1998), Turbulence Modeling for CFD (2nd ed.), DCW Industries, ISBN 0963605100
- Bradshaw, P. (1971), An introduction to turbulence and its measurement, Pergamon Press, ISBN 0080166210
- Versteeg, H.; Malalasekera, W. (2007), An Introduction to Computational Fluid Dynamics: The Finite Volume Method (2nd ed.), Pearson Education Limited, ISBN 978-0131274983
External links
[edit]- CFD Online Wilcox k–omega turbulence model description, retrieved May 12, 2014