The Laminar Flow version of the Rotating Machinery, High Mach Number Flow (hmnf) interface (), found under the High Mach Number Flow > Rotating Machinery, High Mach Number Flow branch (), is used to simulate gas flows in geometries with one or more rotating parts and gas at low and moderate Reynolds number where the velocity magnitude is comparable to the speed of sound, that is, laminar flows in the transonic and supersonic range. This state is often connected to very low pressures. The physics interface is available for 3D and 2D components and it combines the High Mach Number Flow, Laminar interface (), with a Rotating Domain under Definitions > Moving Mesh.

There are two study types available for this physics interface. Using the Time Dependent study type, rotation is achieved through moving mesh functionality, also known as sliding mesh. Using the Frozen Rotor study type, the rotating parts are kept frozen in position, and rotation is accounted for by the inclusion of centrifugal and Coriolis forces. In both types, the physics interface solves for conservation of energy, mass, and momentum. The physics interface also supports heat transfer in solids as well as surface-to-surface radiation. However, only fluid domains adjacent to pair boundaries are supported.

When this multiphysics interface is added, the following default nodes are also added in the Model Builder under High Mach Number Flow, Laminar — Fluid, Initial Values, Wall, and Thermal Insulation. When a pair boundary is created, the Continuity node is automatically added. Then, from the Physics toolbar, add other nodes that implement, for example, boundary conditions, volume forces, and heat sources. You can also right-click the node to select physics features from the context menu. See Moving Mesh for more details on the Rotating Domain node added automatically in the Model Builder under Definitions > Moving Mesh.

The Label is the default physics interface name.

The Name is used primarily as a scope prefix for variables defined by the physics interface. Refer to such physics interface variables in expressions using the pattern <name>.<variable_name>. In order to distinguish between variables belonging to different physics interfaces, the name string must be unique. Only letters, numbers, and underscores (_) are permitted in the Name field. The first character must be a letter.

The default Name (for the first physics interface in the model) is hmnf.

The Reference temperature Tref is used to define the reference enthalpy Href which is set to 0 J/kg at pref (1 atm) and Tref. When the Include kinetic energy checkbox is selected, the conservative total-energy equation is solved.

By definition, no turbulence model is needed when studying laminar flows. The default is None.

The dependent variables (field variables) are the Velocity field u (SI unit: m/s), the Pressure p (SI unit: Pa), and the Temperature T (SI unit: K). The names can be changed but the names of fields and dependent variables must be unique within a component.

To display this section, click the Show More Options button () and select Advanced Physics Options in the Show More Options dialog. Normally these settings do not need to be changed.

Select the Use pseudo time stepping for stationary equation form checkbox to add pseudo time derivatives to the equation when the Stationary equation form is used. When selected, also choose a CFL number expression — Automatic (the default) or Manual. Automatic calculates the local CFL number (from the Courant–Friedrichs–Lewy condition) from a built-in expression. For Manual enter a Local CFL number CFLloc.

By default the Enable conversions between material and spatial frames checkbox is selected.