Reynolds Stress Regions Reference

This section details the conditions that are required for each region type that is supported by the Reynolds Stress turbulence model. In addition, information is provided about the values for each region type.

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

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

Fluid Region

Turbulence Source Option

Controls whether you want to use a turbulence source term.

Turbulence Source Option	Corresponding Value Nodes
Deactivated	None
Activated	Reynolds Stress User Sources Scalar profile values to specify turbulence sources for the components of the Reynolds Stress tensor directly: UU Stress User Source UV Stress User Source UW Stress User Source VV Stress User Source VW Stress User Source WW Stress User Source Reynolds Stress User Source Derivatives Scalar profile values to specify the derivatives of the turbulence sources for the components of the Reynolds Stress tensor directly: UU Stress User Source Derivative UV Stress User Source Derivative UW Stress User Source Derivative VV Stress User Source Derivative VW Stress User Source Derivative WW Stress User Source Derivative Turbulent Dissipation Rate Source Scalar profile value to specify a turbulence source for $ε$ directly. Turbulent Dissipation Rate Source Derivative Scalar profile value to specify the derivative of a turbulent dissipation rate source against dissipation rate directly.

Turbulence Source Option

Corresponding Value Nodes

Deactivated

None

Activated

Reynolds Stress User Sources

Scalar profile values to specify turbulence sources for the components of the Reynolds Stress tensor directly:

UU Stress User Source
UV Stress User Source
UW Stress User Source
VV Stress User Source
VW Stress User Source
WW Stress User Source

Reynolds Stress User Source Derivatives

Scalar profile values to specify the derivatives of the turbulence sources for the components of the Reynolds Stress tensor directly:

UU Stress User Source Derivative
UV Stress User Source Derivative
UW Stress User Source Derivative
VV Stress User Source Derivative
VW Stress User Source Derivative
WW Stress User Source Derivative

Turbulent Dissipation Rate Source

Scalar profile value to specify a turbulence source for

ε

directly.

Turbulent Dissipation Rate Source Derivative

Scalar profile value to specify the derivative of a turbulent dissipation rate source against dissipation rate directly.

Porous Region

Turbulence Specification

Controls how you define the turbulence profile.

The Reynolds Stress model requires the Reynolds stress tensor $R$ and the turbulent dissipation rate $ε$ . The corresponding values are derived from other turbulence quantities.

Method	Corresponding Value Nodes
K + Epsilon Calculation of $R$ from the turbulent kinetic energy $k$ using Eqn. (1366).	Turbulent Kinetic Energy Scalar profile value to specify $k$ . Turbulent Dissipation Rate Scalar profile value to specify $ε$ directly.
Intensity + Length Scale Calculation of $R$ and $ε$ from a specified turbulence intensity $I$ and length scale $L$ using Eqn. (1362) and Eqn. (1364). 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 $R$ and $ε$ from a specified turbulence intensity $I$ and the ratio of turbulent to laminar viscosity $μ_{t} / μ$ using Eqn. (1363) and Eqn. (1365). 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 + Epsilon

Calculation of $R$ from the turbulent kinetic energy $k$ using Eqn. (1366).

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

Intensity + Length Scale

Calculation of $R$ and $ε$ from a specified turbulence intensity $I$ and length scale $L$ using Eqn. (1362) and Eqn. (1364).

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 $R$ and $ε$ from a specified turbulence intensity $I$ and the ratio of turbulent to laminar viscosity $μ_{t} / μ$ using Eqn. (1363) and Eqn. (1365).

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 $μ_{t} / μ$ .