Coupling Participants

System Coupling supports two specialized server participants that are used for aerodamping co-simulations:

  • Mechanical Server

    • ParticipantType = MECH-SRV

  • CFD Server

    • ParticipantType = CFD-SRV

 

Verify Coupling Participant Input Files

Verify that the necessary input file has been generated for each coupling participant. You will use these files to add the participants to the aerodamping co-simulation.

Mechanical Server

  • Input Files: Mechanical modal analysis results file (.rst).

    Note:  If modal mass is defined, a .mode file is also used.

  • For information on how to perform the modal analysis and to generate this file, see Modal Analysis in the Mechanical User's Guide.

CFD Server
 

Add Coupling Participants

Once you have the participant input files, you may add the participants to the aerodamping co-simulation using either System Coupling's GUI or CLI.

Add a participant in the GUI:

  1. Right-click the Setup branch and select Add Participant.

  2. In the Open dialog, select the participant's input file (.rst or .csv).

Add a participant in the CLI:

Run the AddParticipant() command, as shown in the following examples:

  • Add the Mechanical Server participant using the file.rst results file located in Mechanical's modal directory:

    
AddParticipant(ParticipantType = 'MECH-SRV', InputFile = os.path.join('modal', 'file.rst'))

  • Add the CFD Server participant using the input.csv file located in CFX's cfd directory:

    
AddParticipant(ParticipantType = 'CFD-SRV', InputFile = os.path.join('cfd, 'input.csv'))
 

Define the Mechanical Server

The Mechanical Server participant defines one or more surface regions that are available to transfer the data. Since this participant is used only as the source for mapping the data to the CFD Server, it will define only the output variables.

Note:  In the System Coupling GUI, the Input Variables setting is disabled for regions and may be disregarded.

Variable Names

By default, Mechanical Server's mode shape Variable objects are named according to the following conventions:

  • For modal analyses with cyclic symmetry: ModeShape_Mode<N>_HI<M>, where N is the mode number and M is the harmonic index

  • For modal analyses without cyclic symmetry: ModeShape_Mode<N>, where N is the mode number

You may change the variable's DisplayName, if you wish.

Variable Properties

Each mode shape variable is described by the following properties:

  • DataType: Real or Complex. If the modal analysis model features cyclic symmetry, the base and duplicate pair mode shapes form the real and imaginary components of complex mode shapes.

  • QuantityType: Mode Shape

  • TensorType: Vector

  • IsExtensive: False (meaning that the variable is intensive)

Variable Attributes

Each mode shape variable is further described by specialized attributes defined as Attribute objects:

  • Frequency: The frequency for this mode shape (in Hz).

  • MaxDisplacement: The maximum displacement value for the entire mode. Note that Mechanical Server normalizes each mode shape by the maximum displacement value.

  • ModeNumber: The mode number of a given mode shape variable (integer).

  • Mass: The mass value for the entire model.

 

Define the CFD Server

The CFD Server participant typically defines the surface regions that can receive mode shape values from the Mechanical Server participant. Note that input variables are not usually defined by the participant. Instead, you will typically define the variables to be received when you set up the coupling interface in System Coupling.

Note:  In the System Coupling GUI, the Input Variables and Output Variables settings are disabled for regions and may be disregarded.

Optionally, as part of your setup, you may also:

 
Set Execution Control Parameters

CFD Server has several specialized parameters in its ExecutionControl object. You my use these parameters to customize its behavior:

  • BaseOutputFileName

    The base output file name that is used to create the output file.

    By default, the value of this parameter is output, which means that the resulting output files written by CFD Server will be named according to the convention output_<variable name>.csv.

  • OverwriteExistingFiles

    Boolean flag that tells CFD Server how it should behave if the file already exists:

    • False: Issue an error and do not overwrite the file. (default value)

    • True: Overwrite the file without issuing an error.

 
Define Participant Instancing

You can use System Coupling's interface instancing capabilities to apply instancing to a CFD Server participant.

To define participant instancing for CFD Server, perform the following steps:

  1. In System Coupling's Library, create an Instancing object, as described in Adding Instancing Objects.

  2. Define an instancing object on CFD Server using its CouplingParticipant.Instancing setting, as follows:

    If using the GUI:

    1. In the outline, select the CFD Server participant.

    2. Under properties, select an instancing object from the Instancing setting's drop-down menu.

    If using the CLI:

    Define an instancing object on the participant, as shown below:

    
DatamodelRoot().CouplingParticipant['CFD-SRV]'.Instancing = 'Instance-1'

    If no value is provided for this setting, then it defaults to None (no instancing is defined).

Once participant instancing is defined, CFD-Server handles all aspects of the instancing and provides relevant information as arguments for its execution command. When the case is run, CFD Server provides a mesh that contains all instances.

Participant instancing objects have the same options, behaviors, and validations as interface instancing objects. For details, see Defining Interface Instancing for Cylindrical Geometry Models in this guide and Instancing in the System Coupling Settings & Commands Reference documentation.