Turbulence Model Options

By default, Discovery will automatically determine the fluid flow modeling method for you based on the physics inputs. You can explicitly set the modeling method by going to Simulation Options in the ribbon of the Simulation tab and make modifications under Additional Fluid Flow Options.

Select Specify modeling method to override the method set by Discovery. Choose one of the turbulence models if modeling turbulent flow. Alternatively, if the flow is not turbulent, set the fluid flow modeling method to Laminar.

The table below provides information about each of the turbulence options.


k-omega SST	A turbulence model that allows more accurate resolution of boundary layer behavior as the near wall resolution is refined. This model is useful also for free-stream flows, in particular, flows with adverse pressure gradients, flows around airfoils, etc. This model is appropriate for most industrial flows, and is therefore the default model. Where the near wall mesh resolution is coarse, the SST model assumes the boundary layer is fully developed. This is not always the case, especially under adverse pressure gradients when flows decelerate. Under these conditions, the SST model allows you to refine the near wall mesh and capture boundary layer instabilities which lead to separation. If this occurs, then you should switch to the k-omega standard model. k-omega models are typically better in predicting flow separation, and this is one reason why the k-omega SST model is among the most widely used models for aerodynamic flows.
k-epsilon standard	A general industrial model that has historically been used heavily in fluid flow simulations. The wall treatment for this model assumes a fully developed boundary layer, which is not often valid. The omega-based models offer a more consistent wall treatment. This model is available in Refine.
k-omega standard	A general industrial model that offers a reasonable compromise of accuracy and robustness and is generally conservative on separation prediction. This model is available in Refine.
k-epsilon realizable	A general industrial model that is a fair compromise between accuracy and robustness for many industrial applications. The k-omega-based SST and standard models are a better alternative and offer a more consistent wall treatment. Other, newer models, such as the k-omega SST model, offer various improvements over the historic realizable k-epsilon model and are normally favored. For cases where the flow separates under adverse pressure gradients from smooth surfaces (airfoils, etc.), k-epsilon models are generally not recommended as they can lead to overly optimistic design evaluations. This is one reason why k-epsilon models are not widely used in external aerodynamics. For cases where the flow separates under adverse pressure gradients from smooth surfaces (airfoils, etc.), k-epsilon models are generally not recommended as they can lead to overly optimistic design evaluations. This model is available in Refine.
Spalart-Allmaras	A computationally efficient one equation model designed for aerodynamics/aerospace applications. This model is available in Refine (not with the LiveGX solver).
Smagorinsky (LES)	A turbulence model that solves for large-scale fluctuating motions and uses "sub-grid" scale turbulence models for the small-scale motion. Time-dependent equations are solved for the turbulent motion with equations filtered in some way to remove very fine time and length scales. This model is available for time-dependent simulations in Explore.