Post-Processing Harmonic Balance Solution Data

Harmonic Balance offers the ability to visualize a flow variable either in the time domain (for example, at specific time instants) or in the frequency domain (for example, the Real component of the second Fourier mode).

Post-processing for harmonic balance solution data offers the following features:

  • For every blade row, the solution can be reconstructed and visualized in one or more blade passages, and not just in the modeled blade passage.

  • The solution can be reconstructed and plotted at any instant of time.
  • The solution views can be easily switched between time domain and frequency domain visualization. This can be helpful for understanding the unsteady flow features.

You can examine and analyze the results of a harmonic balance simulation on two different representations. When you visualize field functions that represent unsteady or time-varying quantities in a scene, report, or plot, the Representation determines the meaning of the displayed solution field. The choice of representation does not influence the meaning of time-invariant quantities. You can choose between the following representations:

  • Volume Mesh—displays the time-mean solution field.
  • HB Solution View—displays the state of the solution as selected in the corresponding HB Solution View node, such as physical time, Fourier mode, time-level, or filtered mode.

To visualize Harmonic Balance solution data:

  1. Create a scalar or a vector scene and select a field function, for example, Temperature.
  2. Select the Scenes > [scene] > [displayer] node. By default, Representation is set to Volume Mesh.
    The following screenshot shows the time-mean temperature solution on two meshed blade rows, both displaying only the modeled blade passage. This time-mean temperature is displayed on the Volume Mesh representation.


    If you have visualized the variable as part of a steady-state simulation on the blade row geometry, now you can activate the Harmonic Balance model and still retain the visualization.

  3. To visualize the Harmonic Balance solution in different modes and on multiple blade passages, create an HB Solution View:
    1. Right-click Continua > Physics > Models > Harmonic Balance Flow and Energy and select New HB Solution View.
    2. Select the Solution Views > HB Solution View and set Mode to one of the following:
      • Physical Time
      • Time Level
      • Fourier Mode
      • Filtered Mode
      Select the corresponding method subnode and set its properties.

      For more information, see HB Solution View Properties

    3. To specify the number of blade passages to be visualized for each blade row, select the HB Solution View > Blade Rows > [blade row] node and set Blade Passage Selection. Enter the blade passage selection as an ordered pair in square brackets, with a negative integer for the number of lagging blades and a positive integer for the number of leading blades.
      For example:
      • [0, 0] is the original blade alone.
      • [-1, 1] is one lagging blade through one leading blade yielding three blade passages.

      For more information, see Blade Rows.

    4. To display the results in terms of the defined HB Solution View in the graphics window, do one of the following:
      • Select the Scenes > [scene] > [displayer] node and set Representation to [HB Solution View].
      • Select the Solutions Views > [HB Solution View] node and drag and drop it onto the graphics window.
      You can apply the defined HB Solution View representation in similar fashion to reports and plots.
    The following screenshot shows the temperature at a physical time of 0.001 s on three blade passages for the first blade row and four blade passages for the second blade row.

  4. To visualize a field function in a different mode or on a different number of blade passages, you can create additional HB Solution Views.
    For example, using the following settings in another HB Solution View:
    Node Property Setting
    HB Solution View 2 Mode Fourier Mode
    Fourier Mode Mode 1
    Output Option Real
    Blade Rows
    Blade Row 1 Blade Passage Selection [-1,1]
    Blade Row 2 Blade Passage Selection [0,1]
    results in the following temperature distribution.
    Rename the HB Solution View 2 node to HBSolutionView-FourierMode, then drag-and-drop it to the graphics window to display the Fourier mode temperature scene.