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Performing a thermal correlation analysis on a transient problem
In this tutorial, you will learn how to set up and solve a thermal correlation analysis, analyze the results, and update the model with the optimized results for a transient problem.
7. Create the design variables.
You will use the multiplier and substitution methods to create design variables from the boundary condition parameters that are present in the correlated solution.

Tutorials
- TMG Correlation tutorials
  These examples are designed to help you become familiar with some of the major features available in TMG Correlation.
- Performing a thermal correlation analysis on a steady state problem
  In this tutorial, you will learn how to set up and solve a thermal correlation analysis, analyze the results, and update the model with the optimized results for a steady-state problem.
- Performing a thermal correlation analysis on a transient problem
  In this tutorial, you will learn how to set up and solve a thermal correlation analysis, analyze the results, and update the model with the optimized results for a transient problem.
  - 1. Open the Simulation file.
    In addition to opening the file used for this tutorial, you will reset the dialog boxes to ensure that they are in the expected initial state.
  - 2. Examine the model.
    Use the Simulation Navigator to explore the model.
  - 3. Create a thermal correlation analysis.
    You will create a thermal correlation analysis in Simcenter 3D or NX using TMG Correlation.
  - 4. Define the sensors.
    You will create four sensors by importing reference data from a CSV file and by using existing points created previously in the original model.
  - 5. Pair the sensors with the simulation model.
    You will pair the sensors with the elements of the simulation model using the proximity method.
  - 6. Inspect the difference between the reference data and the original solution.
    You will compare the reference temperatures and the original solution temperatures to see the temperature difference between your model and the satellite test data while running the thermal correlation analysis.
  - 7. Create the design variables.
    You will use the multiplier and substitution methods to create design variables from the boundary condition parameters that are present in the correlated solution.
  - 8. Set up the targets.
    You will set the weight factor of the bus targets for the optimization process.
  - 9. Define the optimization design variables.
    You will specify the minimum, and maximum values of the four design variables you previously created to limit their variation during the optimization process.
  - 10. Set up the solver settings.
    You will define the TMG Correlation solver parameters for the optimization.
  - 11. Solve the thermal correlation analysis.
    You will launch the optimization of the active thermal correlation analysis.
  - 12. Plot the thermal correlation graph during the optimization process.
    The Solution Monitor dialog box is still open from the previous step. During the solve, you will plot the evolution of the objective function and the evolution of the design variables gradient.
  - 13. Analyze the optimized solution results.
    You will load and analyze the optimized solution results after solving the thermal correlation analysis.
  - 14. Plot the optimization results.
    You will compare the reference, original, and optimized temperature values for four targets after solving a thermal correlation analysis on the same plot.
  - 15. Update the simulation model.
    You will update and save the new simulation model that contains the optimized design variable values applied to the related parameters.

7. Create the design variables.

You will use the multiplier and substitution methods to create design variables from the boundary condition parameters that are present in the correlated solution.

In the TMG Correlation dialog box, select the Design Variables > Definition node.
In the Parameters and Expressions group, from the Type list, make sure that Parameters is selected.
Expand the Filter subgroup, and select the Source Type check box.
From the Source Type list, select Heat Load.
Click Filter to only display the heat load sources in the Parameter and Expression table.
From the Parameters and Expressions table, select Heat Load.
In the Design Variable Definition group, from the Design Variable Method list, select Substitution to replace the Heat Load by a design variable.
In the Design Variable Name box, type DV1_Heat_Load.
Click Add Design Variable to add the DV1_Heat_Load design variable to the active thermal correlation analysis.
In the Filter group, from the Source Type list, make sure that Contact Thermal Coupling is selected.
Click Filter to only display the contact thermal coupling sources in the Parameters and Expressions table.
From the Parameters and Expressions table, select Total Conductance.
From the Design Variable Method list, select Multiplier to multiply the parameter by a design variable.
In the Design Variable Definition group, in the Design Variable Name box, type DV2_antena_bus_TCTC_Total_Conductance.
Click Add Design Variable to add the design variable to the active thermal correlation analysis.
From the Parameters and Expressions table, select Heat Transfer Coefficient.
In the Design Variable Definition group, in the Design Variable Name box, type DV3_walls_mass_TCTC_Heat_Transfer_Coefficient.
Click Add Design Variable to add the design variable to the active thermal correlation analysis.
From the Parameters and Expressions table, select the two Conductance per Length parameters.
In the Design Variable Definition group, in the Design Variable Name box, type DV4_panel_bus_conductance.
Click Add Design Variable to add the design variable to the active thermal correlation analysis.