Specifying the Coupled Boundary and Exchanged Fields

Define the fluid-structure interface and the fields that are exchanged during co-simulation. In this simulation, Simcenter STAR-CCM+ computes the fluid pressure and wall shear stress and Simcenter Nastran computes the disc displacement. The morpher updates the fluid mesh to account for the displacement of the solid disc at the fluid-structure interface.

To define the fluid-structure interface:
  1. Expand the Regions > Fluid > Boundaries > WallFSI > Physics Conditions node.
  2. Select the External Code Coupling Specification node and set External Code Coupling Specification to Link 1: Zone 1.
    Simcenter STAR-CCM+ automatically adds the WallFSI boundary to the Zone 1 coupled model parts.
To account for the solid displacement at the fluid-structure interface, define a morphing motion for the fluid region:
  1. Right-click the Tools > Motions node and select New > Morphing.
  2. Select the Morphing node and set Morpher Method to RBF.
  3. Select the Regions > Fluid > Physics Values > Motion Specification node and set Motion to Morphing.
To specify the fields exchanged with Simcenter Nastran:
  1. Expand the External Links > Link 1 > Zones > Zone 1 > Conditions node.
  2. Right-click the Exported Fields node and select Add Mechanical Field > Pressure.
  3. Right-click the Exported Fields node and select Add Mechanical Field > Wall Shear Stress.
  4. Right-click the Imported Fields node and select Add Mechanical Field > Displacement.
  5. Select the Imported Fields > Displacement node and set Field Treatment to Managed.
    With this setting, Simcenter STAR-CCM+ automatically sets the morphing specification for the coupled boundary, so that the coupled fluid boundary moves according to the imported disc displacement.
By default, Simcenter STAR-CCM+ creates a single data mapper for data interpolation. In general, it is recommended to have separate data mappers for incoming and outgoing fields.
  1. Expand the Tools > Data Mappers node.
  2. Rename the Default Surface Co-simulation Mapper 1 node to Traction Mapper.
To create an additional mapper for the displacement field:
  1. Right-click the Data Mappers node and select New Data Mapper > Surface Data Mapper.
  2. Rename the Data Mappers > Surface Data Mapper 1 node to Displacement Mapper.
    The default stencil (vertex) and interpolation method (shape function) are appropriate.
Assign the new mapper to the imported displacement field:
  1. Expand the External Links > Link 1 > Zones > Zone 1 > Values > Import Mappers node.
  2. Select the Displacement node and set Mapper to Displacement Mapper.
    Simcenter STAR-CCM+ automatically sets the source and target surfaces for the mappers when you run the co-simulation.
  3. Save the simulation.