The Rotating Machinery, Turbulent Flow, Low Re k-ε (spf) interface (), found under the Single-Phase Flow > Rotating Machinery branch () when adding a physics interface, is used to simulate flow at high Reynolds numbers in geometries with one or more rotating parts. The physics interface supports incompressible, weakly compressible and compressible flows at low Mach numbers (typically less than 0.3). The physics interface is available for 3D and 2D components.

The momentum balance is governed by the Navier–Stokes equations, and the mass conservation is governed by the continuity equation. Turbulence effects are modeled using the AKN two-equation k-ε model with realizability constraints. The AKN model is a so-called low-Reynolds number model, which means that it resolves the flow all the way down to the wall. The AKN model depends on the distance to the closest wall. The physics interface therefore includes a wall distance equation.

There are two study types available for this physics interface. Using the Time Dependent with Initialization study type, the rotation is achieved through moving mesh functionality, also known as sliding mesh. Using the Frozen Rotor with Initialization study type, the rotating parts are kept frozen in position, and the rotation is accounted for by the inclusion of centrifugal and Coriolis forces. See Theory for the Rotating Machinery Interfaces in the CFD Module User’s Guide. In both study types initialization is performed by first solving for the distance to the closest wall.

When this physics interface is added, the following physics nodes are also added in the Model Builder under Turbulent Flow, Low Re k-ε — Fluid Properties, Wall, and Initial Values. A Moving Mesh interface with a Rotating Domain node is added automatically in the Model Builder under the Definitions node. Then, from the Physics toolbar, add other nodes that implement, for example, boundary conditions and volume forces. You can also right-click Turbulent Flow, Low Re k-ε to select physics features from the context menu. For information about the available physics features, see Domain, Boundary, Point, and Pair Nodes for the Rotating Machinery Interfaces.

A part for the interface settings defined below, see the advanced settings defined for The Rotating Machinery, Laminar Flow Interface, and the settings in The Creeping Flow, Laminar Flow, Turbulent Flow, Large Eddy Simulation, and Detached Eddy Simulation Interfaces in the CFD Module User’s Guide.

For this physics interface the parameters are Ce1, Ce2, Cμ, σk, σe, and κv.