# Selection of Turbulent Model

Submitted by ken on February 4, 2014 - 09:26

Is there a single document where I can get a one or two sentence explanation of the best application of each of these 17 turblence models available to me. I have rummaged around the internet and things are too dispersed between these models. I am looking for information under which each would be applied rather than a technical description of its derivation. Surely there are subtile differences between similar models and some differences may tied to computation time rather than the application.

Thanks

## Turbulence modeling is a complex field

Turbulence modeling is a complex field. Trying to strike a balance between accuracy and computational efficiency has given rise to a relatively large number of different turbulence models. For more details see "RANS-based turbulence models". There is no definitive list to match turbulence models to applications.

In Caedium the default turbulence model is

k-omega SSTwhich is considered to be a relatively robust, accurate, and efficient model for a wide range of applications. Unless you are seeing results that call this into question I would suggest you stick with this model. Before considering a different turbulence model first remember that poor results are often due to:Also note that using wall functions (as for the majority of turbulence models in Caedium), to avoid extremely fine near wall meshes, requires that the y+ values be in the range 30-300 for the best results.

Independent of the turbulence model to improve accuracy, sometimes at the expense of robustness, you can try:

Substance->Solver->Schemes->Divergence = Linear UpwindPhysics:Wall->Type:Default->nut = U Spalding Wall FunctionIf you know that the fluid flow is likely to be entirely laminar due to the Reynolds number (e.g., in a pipe flow with Re < 2300) then you should switch the turbulence model to

Laminar.If you'd like to try another widely used and reliable turbulence model then I'd suggest the

Realizable k-epsilon.## thanks for the advice... very

thanks for the advice... very helpful