Specifying Co-Simulation Settings

Prepare the fluid simulation for co-simulation. Setting up a co-simulation requires you to activate a co-simulation model and to specify the coupled boundaries and the fields exchanged with the partner code.

The fluid simulation couples with the Simcenter STAR-CCM+ API server associated with the partner code. As the Simcenter STAR-CCM+ API server has all the features of a Simcenter STAR-CCM+ simulation, you specify the co-simulation settings in the fluid simulation as you would do for a standard Simcenter STAR-CCM+ to Simcenter STAR-CCM+ co-simulation.

To enable co-simulation, activate a Simcenter STAR-CCM+ Co-Simulation model:

  1. For the physics continuum, Continua > Fluid Physics, select the following models in order:
    Group box Model
    Optional Models Co-Simulation
    Co-Simulation Models Simcenter STAR-CCM+
    Co-Simulation Treatment Models Co-Simulation Mechanical Treatment
  2. Click Close.
To couple the fluid with the solid that is defined in the partner simulation, you require an additional physics continuum that represents the solid physics.
  1. Create a physics continuum named Solid Physics (External).
  2. For the physics continuum, Solid Physics (External), select the following models in order:
    Group box Model
    Optional Models External Continuum
    External Continuum External Application
    Space Surface Three Dimensional
    External Application Simcenter STAR-CCM+
    Coupling Models Implicit Coupling
    Time Implicit Unsteady (selected automatically)
When you activate co-simulation models, Simcenter STAR-CCM+ adds a co-simulation link node, External Links > Link 1. This node represents a connection to an external application and allows you to specify co-simulation settings.

For this link, specify the external continuum that represents the external application:

  1. Select the External Links > Link 1 > Conditions > External Continua node and set Continua to Solid Physics (External).
To define the fluid-structure interface, assign the coupled fluid boundary to a co-simulation zone:
  1. Expand the Regions > Spindle Valve Fluid > Boundaries > spindleball > Physics Conditions node.
  2. Select the External Code Coupling Specification node and set External Code Coupling Specification to Link 1: Zone 1.
    Once you associate a boundary to a coupling zone, Simcenter STAR-CCM+ updates the Coupled Model Parts condition for that zone.

In this co-simulation, Simcenter STAR-CCM+ imports displacements from the external program and exports pressure and wall shear stress. To specify the exchanged fields:
  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. Repeat the previous step to add Wall Shear Stress to the exported fields.
  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 boundary moves according to the imported displacement data.
Specify the number of inner iterations between exchanges:
  1. Select the Link 1 > Values > Field Exchange Controls node and set Iterations Per Exchange to 5.
    By default, the Simcenter STAR-CCM+ server is the leading simulation.