The Turbulent Flow, k-
ε (spf) interface (
) is used for simulating single-phase flows at high Reynolds numbers. The physics interface is suitable for incompressible flows, weakly compressible flows, and compressible flows at low Mach numbers (typically less than 0.3).
The equations solved by the Turbulent Flow, k-ε interface are the Reynolds-averaged Navier-Stokes (RANS) equations for conservation of momentum and the continuity equation for conservation of mass. Turbulence effects are modeled using the standard two-equation
k-
ε model with realizability constraints. The flow near walls is modeled using wall functions.
The Turbulent Flow, k-ε interface can be used for stationary and time-dependent analyses. The main feature is Fluid Properties, which adds the RANS equations and the transport equations for
k and
ε, and provides an interface for defining the fluid material and its properties. When this physics interface is added, the following default nodes are also added in the
Model Builder:
Fluid Properties, and
Initial Values.
A different turbulence model can be selected under Turbulence model.
Laminar or creeping flow may be simulated by changing the
Turbulence model type to
None.
Wall treatment for the k-
ε model can only be set to
Wall functions. More options becomes available by selecting another option under
Turbulence model.
The Turbulence model property disables the
Neglect inertial term (Stokes flow) check box, and for 2D components also the
Shallow Channel Approximation check box.
To display this section, click the Show More Options button (
) and select
Advanced Physics Options in the
Show More Options dialog box. The
Turbulence variables scale parameters subsection is available when the
Turbulence model type is set to
RANS.
The Uscale and
Lfact parameters are used to calculate absolute tolerances for the turbulence variables. The scaling parameters must only contain numerical values, units or parameters defined under
Global Definitions. The scaling parameters cannot contain variables. The parameters are used when a new default solver for a transient study step is generated. If you change the parameters, the new values take effect the next time you generate a new default solver