The Rotating Machinery, Turbulent Flow, Spalart–Allmaras (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.

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, Spalart–Allmaras — 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, Spalart–Allmaras 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 Cb1, Cb2, Cv1, σv, Cw2, Cw3, κv, and Crot.

To display this section, click the Show More Options button () and select Advanced Physics Options in the Show More Options dialog. Under the Turbulence variables scale parameters subsection, the default νscale is of the same order of magnitude as the kinematic viscosity of air at room temperature.