Creating Regions, Boundaries, and Interfaces

This simulation requires two regions, one for the solid manifold and one for the fluid. The two regions exchange thermal data at a fluid-solid interface. The fluid region contains an internal interface between the fluid inside the manifold and the fluid extrusion at the outlet.

In this simulation, you group multiple part surfaces under the same boundaries, based on the physics conditions that you apply. For this reason, it is convenient to create the regions and boundaries manually, rather than using the Assign Parts to Regions dialog.

To create the fluid region:

  1. Expand the Geometry > Parts node and multi-select Fluid Outlet Extrusion and Internal Fluid.
  2. Right-click one of the selected part and select Set New Region...
  3. Set New Region Name to Fluid and click OK.
  4. Expand the Regions > Fluid > Boundaries node.
  5. Rename the Default node to Fluid Wall.
  6. Right-click the Boundaries node and create a new boundary
  7. Rename the Boundary 1 node to Inlets.
  8. For the Inlets boundary, set the following properties:
    Property Setting
    Part Surfaces Internal Fluid > Fill Holes > Manifold.ToCylinderHead
    Type Mass Flow Inlet
  9. Following the same procedure, create a new boundary and rename it to Outlet and set the following properties:
    Property Setting
    Part Surfaces
    • Fluid Outlet Extrusion > Surfaces > Fill Holes.Manifold.ToTurbo
    • Fluid Outlet Extrusion > Internal Fluid > Fill Holes > Manifold.ToTurbo
    • Internal Fluid > Fill Holes > Manifold.ToTurbo
    Type Pressure Outlet
In general, it is good practice to assign the surfaces that belong to an interface to a separate boundary. This practice is useful when troubleshooting interface issues, as you can check whether the boundary faces are correctly mapped to the interface boundary. To create a boundary for the fluid surfaces that interface the solid:
  1. Within the Fluid region, create a new boundary.
  2. Rename the Boundary 1 node to ToManifold and set the following properties:
    Property Setting
    Part Surfaces Internal Fluid > Manifold > ToInternalFluid
    Type Wall


To create the solid region:
  1. Right-click the Geometry > Parts > Manifold node and select Set Region > New.
  2. Set New Region Name to Manifold and click OK.
  3. Select the Regions > Manifold node and set Type to Solid Region.
  4. Rename the Manifold > Boundaries > Default node to External.
  5. Right-click the Boundaries node and create new boundaries with the following settings:
    Boundary Name Part Surfaces
    ToCylinderHead ToCylinderHead
    ToInternalFluid ToInternalFluid
    ToTurbo ToTurbo


This simulation requires two interfaces—one interface in the fluid region between the internal fluid and the fluid extrusion, and one interface between the fluid and the solid regions. As the fluid and the solid domains use different discretization methods for the CHT solution (finite volume for the fluid and finite element for the solid), you require a non-conformal interface at which data is mapped between the different mesh representations.

To create the internal interface between the fluid extrusion and the internal fluid:

  1. Expand the Geometry > Contacts node.
  2. Right-click the Internal Fluid/Fluid Outlet Extrusion > Fill Holes.Manifold.ToTurbo/Internal Fluid.Fill Holes.Manifold.ToTurbo node and select Set New Interface...
To create the interface between the fluid and the manifold:
  1. Right-click the Manifold/Internal Fluid > ToInternalFluid/Manifold.ToInternalFluid node and select Set New Interface...
  2. Select the Interfaces > Manifold/Fluid node and set Type to Mapped Contact Interface.


  3. Save the simulation.