What Is the High-Reynolds Number Spalart-Allmaras Model?

In the derivation of the model, the authors present a high-Reynolds number version in which the viscous damping within the buffer layer and viscous sublayer is not included. This form of the model, analogous to a K-Epsilon model with wall functions, has also been presented in STAR-CCM+. It is only suited to coarse, wall-function-type meshes where y+ values generally exceed about 30. The standard model with All y+ Wall Treatment ought to give very similar results to this model on coarse meshes. Therefore, it is recommended that the High-Reynolds number formulation be activated only if it is suspected that the viscous damping functions might be adversely affecting results. This is likely to occur if y+ values are in the intermediate range of 10 to 30.

High-Reynolds Number Spalart-Allmaras Properties

Deformation Option

Selects the modified or standard production term.

Modified

Selects the modified production term. This is recommended for most simulations. See Eqn. 175.

Original

Selects the standard production term. This option allows comparison with results from other CFD codes that lack the modified production term. See Eqn. (173).

Convection

For guidance on selecting a convection, see Diffusion Term .

1st-order

Selects the first-order convection.

2nd-order

Selects the second-order convection.

High-Reynolds Number Spalart-Allmaras Expert Properties

Unless you are thoroughly familiar with the theoretical aspects of this model and the discretization techniques used in STAR-CCM+, we recommend that you not make any changes within the Expert category. The values in that category reflect both the model's design and discretization approaches that have been optimized for accuracy and performance. Tampering with them may diminish the effectiveness of the model.