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3

 

 

 

 

 

2

 

 

3

4k3/ 2

k =

--

 

 

U

 

IT

 

,

 

= C

----------

 

 

 

 

2

 

 

 

 

 

 

 

 

 

LT

If Specify turbulence variables is selected, enter values or expressions for the Turbulent kinetic energy k0 (SI unit: m2/s2) and Turbulent dissipation rate, 0 (SI unit: m2/s3).

For the Turbulent Flow, Spalart-Allmaras interface, also enter a value or expression for the Undamped turbulent kinematic viscosity 0 (SI unit: m2/s).

For recommendations of physically sound values see Inlet Values for the

Turbulence Length Scale and Intensity.

Note

Outlet

The Outlet feature includes a set of boundary conditions describing fluid flow and temperature conditions at an outlet. The applied conditions are controlled by the Flow Condition:

Using a Hybrid condition, both subsonic (Ma < 1) and supersonic flow (Ma > 1) conditions at the outlet are supported. This is the default condition.

Select Supersonic when the flow at the outlet is known to be subsonic.

Select Subsonic when the flow at the outlet is known to be subsonic.

For a background of the derivation and implementation of the conditions,

see the Theory for the High Mach Number Interfaces.

See Also

F L O W P R O P E R T I E S

This section displays when the Hybrid or Subsonic condition is selected.

Note

360 | C H A P T E R 1 1 : H I G H M A C H N U M B E R F L O W B R A N C H

Hybrid

Using the Hybrid condition, a outlet pressure is specified. This pressure is enforced at

the outlet when the flow is subsonic.

By default a Static pressure input is used. Enter a value or expression for the Static pressure p0,stat (SI unit: Pa).

If Total is selected, enter a value or expression for the Total pressure p0,tot (SI unit: Pa).

The relation between the static and total pressure is defined in

Equation 11-2.

Note

Subsonic

Using the Subsonic condition, a Pressure or a Normal Stress condition can be applied.

These conditions correspond to the ones for the Single-Phase Laminar

Flow interface. See Inlet and Outlet.

See Also

Selecting appropriate outlet conditions for the Navier-Stokes equations is not a trivial task. Generally, if there is something interesting happening at

an outflow boundary, extend the computational domain to include this

Tip

phenomenon.

T H E H I G H M A C H N U M B E R F L O W I N T E R F A C E S | 361

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