K-Omega Boundaries Reference

This section details the conditions that are required for each boundary type that is supported by the K-Omega turbulence model. In addition, information is provided about the values for each boundary type.

Boundary conditions and values are elected by the boundary type, and/or by methods selected in corresponding nodes in the Conditions node.

Note	Boundary types that do not require setting any conditions or values are not listed.

Flow Boundaries

The following boundary conditions and values are equal to all flow boundaries of type:

Free Stream
Mass Flow Inlet
Pressure Outlet
Stagnation Inlet
Velocity Inlet

Turbulence Specification

Controls how you define the turbulence profile.

The K-Omega model requires the turbulent kinetic energy $k$ and the specific dissipation rate $ω$ . You can enter the corresponding values directly or have them derived from other turbulence quantities.

Method	Corresponding Value Nodes
K + Omega	Turbulent Kinetic Energy Scalar profile value to specify $k$ directly. Specific Dissipation Rate Scalar profile value to specify $ω$ directly.
Intensity + Length Scale Calculation of $k$ and $ω$ from a specified turbulence intensity $I$ and length scale $l$ using Eqn. (1356) and Eqn. (1360). Do not use this method if the velocity field is initialized to zero.	Turbulence Intensity Scalar profile value to specify $I$ . Turbulent Length Scale Scalar profile value to specify $l$ .
Intensity + Viscosity Ratio Calculation of $k$ and $ω$ from a specified turbulence intensity $I$ and viscosity ratio $μ_{t} / μ$ using Eqn. (1357) and Eqn. (1361). Do not use this method if the velocity field is initialized to zero.	Turbulence Intensity As for Intensity + Length Scale. Turbulent Viscosity Ratio Scalar profile value to specify the ratio of turbulent to laminar viscosity $μ_{t} / μ$ .

Method

Corresponding Value Nodes

K + Omega

Turbulent Kinetic Energy: Scalar profile value to specify $k$ directly.
Specific Dissipation Rate: Scalar profile value to specify $ω$ directly.

Intensity + Length Scale

Calculation of $k$ and $ω$ from a specified turbulence intensity $I$ and length scale $l$ using Eqn. (1356) and Eqn. (1360).

Do not use this method if the velocity field is initialized to zero.

Turbulence Intensity: Scalar profile value to specify $I$ .
Turbulent Length Scale: Scalar profile value to specify $l$ .

Intensity + Viscosity Ratio

Calculation of $k$ and $ω$ from a specified turbulence intensity $I$ and viscosity ratio $μ_{t} / μ$ using Eqn. (1357) and Eqn. (1361).

Do not use this method if the velocity field is initialized to zero.

Turbulence Intensity: As for Intensity + Length Scale.
Turbulent Viscosity Ratio: Scalar profile value to specify the ratio of turbulent to laminar viscosity $μ_{t} / μ$ .