In a coupled simulation, Forte and the other participant(s) of System Coupling are applied to distinct simulation domains which share common geometric surfaces. Such a surface, where transfer and mapping of solutions from one to the other participant occur, is called a coupling interface. The data transfer is two-way, meaning that each participant is both a source and target of the data transfer, sending an output and receiving an input.

When setting up the participants for System Coupling, the coupling interface(s) must be properly specified in each participant. Specifically, we need select which boundary condition is the coupling interface and what solutions are to be transferred out and received on the interface.

Also, certain controlling parameters for the coupled simulation, such as the maximum number of coupled iterations, should be specified before starting the simulation.

Here, we provide an overview of the settings needed for Forte and System Coupling to do a coupled simulation. For detailed and step-by-step instructions, refer to How to Set Up and Run a Coupled Simulation.

Forte Settings

The Forte project file (.ftsim) contains all the information needed for System Coupling to accept it as a participant. Unlike some other participants, which must export a System Coupling participant (.scp) file, Forte does not need to export a .scp file. The System Coupling command can load Forte as a participant by directly reading the .ftsim project file.

As mentioned, Forte must have a wall boundary condition listed under the System Coupling node in the Forte Workflow tree. Enable System Coupling under Simulation Controls to make this boundary a coupling interface. For a Conjugate Heat Transfer analysis, select the output variable on the coupling interface as Heat Rate, or alternatively, Heat Transfer Coefficient and Near Wall Temperature. Or, for a Fluid Structure Interaction analysis, select the output variable as Force.

More detailed System Coupling related Forte settings can be found in Step 1: Set up Forte Project for System Coupling.

Settings of Another Participant

The most common participants working with Forte on System Coupling are Ansys Fluent and Ansys Mechanical. In both, the boundaries selected as system coupling interface need to be flagged as system coupling. Both of their projects, once established, must export .scp file to be used by System Coupling for necessary setup.

More information on setting up another participant can be found in Step 2: Set Up the Other Participants for System Coupling.

Set Up a Working Directory

Once the project files of all the System Coupling participants are prepared, they must be placed in a working directory where the System Coupling simulation is performed.

For more details, refer to Step 3: Set Up a Working Folder for the System Coupling Run.

System Coupling Settings

System Coupling settings are needed to define the participants, the coupling interface(s), the data transferred, and to specify controls for the coupled simulation and the output. These settings are managed by either a command-line-based Python script (Step 4a: Create a System Coupling Python Run Script), or by the graphical user interface (Step 4b: Use the System Coupling Graphical User Interface).