Turbulent Viscosity

Turbulent viscosity is a condition for a Domain in the Flow Analysis Tree.

You can specify the type of eddy viscosity model for a selected Domain for the Turbulence module in the Properties panel. There are two models in the eddy viscosity model:

• Standard K-Epsilon Model

You can select the standard k-epilson model and associated constants for a selected Volume for the Turbulence module in the Properties panel.

• Renormalization Group (RNG) Model

You can select the RNG model and the associated constants for a selected Volume under the Turbulence module in the Properties panel. 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: η0=4.38 and β=1.92.

Turb. Viscosity Relaxation

Turb. Viscosity Relaxation in the Turbulence module controls the amount of correction applied during each iteration, using the following formula for the turbulent viscosity. You can set Turb. Viscosity Relaxation for a selected Domain under the Turbulence module in the Properties panel.

The default 0 value of Turb. Viscosity Relaxation is the most liberal and allows full application of the correction. Turb. Viscosity Relaxation ranges from 0 to 1. A value of 0 is recommended if no problem occurs with the convergence. Higher values (>0) are recommended if needed to prevent a solution from diverging. A Turb. Viscosity Relaxation value of 1 is the most restrictive and allows no correction of the solution from one iteration to the next.