SST k-omega model
From CFD-Wiki
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==Kinematic Eddy Viscosity == | ==Kinematic Eddy Viscosity == | ||
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- | \nu _T = {a_1 k \over \mbox{max}(a_1 \omega, | + | \nu _T = {a_1 k \over \mbox{max}(a_1 \omega, S F_2) } |
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- | P_k=\mbox{min} \left(\tau _{ij} {{\partial U_i } \over {\partial x_j }} , | + | P_k=\mbox{min} \left(\tau _{ij} {{\partial U_i } \over {\partial x_j }} , 10\beta^* k \omega \right) |
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Revision as of 10:01, 15 May 2008
The SST k-ω turbulence model [Menter 1993] is a two-equation eddy-viscosity model which has become very popular. The SST formulation combines the best of two worlds. The use of a k-ω formulation in the inner parts of the boundary layer makes the model directly usable all the way down to the wall through the visous sub-layer, hence the SST k-ω model can be used as a Low-Re turbulence model without any extra damping functions. The SST formulation also switches to a k-ε behaviour in the free-stream and thereby avoids the common k-ω problem that the model is too sensitive to the inlet free-stream turbulence properties. Authors who use the SST k-ω model often merit it for its good behaviour in adverse pressure gradients and separating flow. The SST k-ω model does produce a bit too large turbulence levels in regions with large normal strain, like stagnation regions and regions with strong acceleration. This tendency is much less pronounced than with a normal k-ε model though.
Contents |
Kinematic Eddy Viscosity
Turbulence Kinetic Energy
Specific Dissipation Rate
Closure Coefficients and Auxilary Relations
References
- Menter, F. R. (1993), "Zonal Two Equation k-ω Turbulence Models for Aerodynamic Flows", AIAA Paper 93-2906.
- Menter, F. R. (1994), "Two-Equation Eddy-Viscosity Turbulence Models for Engineering Applications", AIAA Journal, vol. 32, pp. 269-289.