12.6.2 Setting Up the RNG $k$- $\epsilon$ Model

If you choose the RNG $k$- $\epsilon$ model, the following options are available:

• differential viscosity model (Section  12.13.5)

• swirl modification (Section  12.13.6)

• viscous heating (always activated for the density-based solvers) (Section  12.13.1)

• inclusion of buoyancy effects on $\epsilon$ (see this section in the separate Theory Guide)

Figure 12.6.2: The Viscous Model Dialog Box Displaying the RNG $k$- $\epsilon$ Model

For all $k$- $\epsilon$ models, one the following near-wall treatments must be selected (see this section in the separate Theory Guide):

• standard wall functions

• non-equilibrium wall functions

• enhanced wall treatment

• user-defined wall functions

If you choose the enhanced wall treatment, the following options are available:

• pressure gradient effects (Section  12.13.10)

• thermal effects (Section  12.13.11)

If you choose the user-defined wall functions near-wall treatment, hook your UDF under Law of the Wall, as shown in Figure  12.6.1.