Defining the Interfaces

The starting simulation includes predefined interfaces between the solid regions. For the newly created fluid regions, you require additional interfaces. Each interface has either an in-place, periodic, or repeating topology.

The Finite Element Magnetic Vector Potential model requires conformal interfaces. This is done automatically when you create the required interfaces.
As you are only modeling a quarter of the full machine, you require periodic interfaces with rotational periodicity.
  1. To create these interfaces:
    1. Right-click the Regions > Motion Specification: Rotation > Rotor Air Box node and select Create Interface.
    2. Repeat the previous step for the following nodes:
      • Motion Specification: Rotation > Rotor Air Gap
      • Motion Specification: Stationary > Stator Air Box
      • Motion Specification: Stationary > Stator Air Gap
    3. Multi-select the interfaces you have just created.
    4. Right-click one of the selected nodes and select Edit.
    5. In the Multiple Object dialog, set the following properties then click Close:
      Node Property Value
      [Interface] Topology Periodic
      Periodic Transformation Periodicity Rotational
      Axis of Rotation Specify Axis
      Axis Direction [1.0, 0.0, 0.0]
      Physics Conditions > Magnetic Vector Potential Periodicity Method Anti-Periodic
      The Anti-Periodic periodicity ensures the magnetic vector potential is positive on one side of the interface and negative on the opposite side. It also reduces the analysis for a model containing an odd number of poles.

  2. Define the interfaces for the contacting regions:
    1. Multi-select the Motion Specification: Rotation > Rotor Air Gap and Motion Specification: Rotation > Rotor Air Box nodes.
    2. Right-click one of the selected nodes and select Create Interface > Contact Mode Boundary Interface.
    3. Repeat the previous two steps for the following regions:
      Region 1 Region 2
      Motion Specification: Stationary > Stator Air Box Motion Specification: Stationary > Stator Air Gap
      Motion Specification: Rotation > Rotor Air Gap Motion Specification: Stationary > Stator Air Gap
      Motion Specification: Stationary > Coils Motion Specification: Stationary > Stator Air Box
      Motion Specification: Rotation > Magnets Motion Specification: Rotation > Rotor Air Box
      Motion Specification: Rotation > Rotor Motion Specification: Rotation > Rotor Air Box
      Motion Specification: Stationary > Stator Air Box Motion Specification: Stationary > Stator Teeth
The Airgap Remeshing model requires a repeating interface where remeshing occurs, that is, between the stationary air gap and the rotating air gap regions.
  1. Select the Interfaces > Stator Air Gap/Rotor Air Gap node and set Topology to Repeating.
  2. Select the Stator Air Gap/Rotor Air Gap > Physics Conditions > Magnetic Vector Potential Periodicity node and set Method to Anti-Periodic.
  3. Expand the Interfaces node and multi-select the following interfaces:
    • Rotor Air Box/Rotor Air Box
    • Rotor Air Gap/Rotor Air Gap
    • Stator Air Box/Stator Air Box
    • Stator Air Gap/Stator Air Gap
    • Rotor Air Gap/Rotor Air Box
    • Stator Air Box/Stator Air Gap
    • Rotor Air Gap/Stator Air Gap
    • Magnets/Rotor Air Box
    • Rotor/Rotor Air Box
    • Stator Air Box/Stator Teeth
    • Coils/Stator Air Box
  4. In the Multiple Objects - Properties panel, set Contacts to Type is Part Surface Contact.


  5. Right-click the Interfaces node and select Group By > Topology.


  6. Save the simulation.