Turbulent Viscosity

Turbulent Viscosity is a volume condition in the Turbulence module pertaining to selected Volumes.

Specify the Turbulent Viscosity as follows:

Geometric Entities Panel > Volumes > [Desired Volume]
Properties Panel > Model Tab > Turbulence > Turbulent Viscosity

The type of Eddy Viscosity Model is specified for a selected volume in the Turbulence module under the Model option.

The two Eddy Viscosity Models are:

Standard K-Epsilon
RNG: The RNG model may be more accurate than the Standard K-Epsilon model for flows with stagnation and separation. The following two additional constants are hard-coded for the RNG model: and .

Each of these models have their set of default values as shown in Figure 5.58, which are discussed in turbulence models.

Figure 5.58 - Turbulent viscosity

Turbulent Viscosity Relaxation

This controls the amount of correction applied during each iteration for the Turbulent Viscosity, using the following formula:

5.159

The default value of Turb. Viscosity Relaxation is 0. It may range from 0 to 1. A Turb. Viscosity Relaxation of 0 is the most liberal, allowing the full correction to be applied. A value of 0 is recommended, assuming no problem with the convergence. A value of 1 is the most restrictive, allowing no correction of the solution from one iteration to the next.