1.2.3. Convergence History Plots and User Point Plots

Convergence history plots and user point plots are shown on monitor tabs. Each monitor tab shows at least one plot of a variable versus time step, where the variable can be an RMS or maximum residual, or a user-defined variable. For example, the Momentum and Mass monitor tab shows plots of the RMS/maximum residuals for pressure and the U, V, and W components of momentum. A legend appears below each plot to show the variable associated with each plot line.

For simulations involving rigid body modeling, additional plots specific to rigid bodies are available. For details, see Monitor Plots related to Rigid Bodies in the CFX-Solver Modeling Guide.

For Transient Blade Row simulations involving the Time Transformation method, the flow equations produce results in "computational time", not "physical time". By default, when plots against Simulation Time are produced, most variables are plotted against computational time, but variables that have a corresponding physical time (for example, monitor points) are plotted against physical time. For details on the Time Transformation method, see Time Transformation in the CFX-Solver Theory Guide.

You can control which plots are active from the Monitors menu.

Some other actions that you can perform:

  • Configure/edit a monitor from the CFX-Solver Manager Monitor Properties Dialog Box dialog box. To invoke that dialog box, you can do one of the following:

    • Right-click in the plot area of the monitor tab and select Monitor Properties from the shortcut menu.

    • Select Workspace > Workspace Properties from the main menu, then select a monitor from the Workspace Properties dialog box and click Edit  .

  • Click any of the plot lines to view the value at the nearest time step.

  • Toggle between showing RMS or maximum values by right-clicking in the monitor tab and selecting Switch Residual Mode from the shortcut menu.

  • Hide or show any monitor tab from the CFX-Solver Manager Monitors Menu. Another way to hide a monitor tab (other than the Out File monitor tab) is to right-click in the monitor tab and select Hide Monitor from the shortcut menu.

  • Delete a monitor tab by right-clicking in the monitor tab and selecting Delete Monitor from the shortcut menu.

Other actions that can be performed using the shortcut menu on the monitor tab are described in the following sections:

1.2.3.1. Changing the Plot Type

You can switch between XY, Cyclic XY, and Polar plots. The XY plot is a standard plot. Cyclic XY and Polar plots are suitable for transient periodic flows, and are described in Chart Type Settings Tab.

1.2.3.2. Printing an Image of the Convergence History

You can print a picture of the convergence history plot:

  1. Right-click in the convergence history plot and select Print.

    The Print dialog box appears.

  2. Configure the printer as required.

  3. Click Print.

1.2.3.3. Saving a Picture of the Convergence History

You can save a picture of the convergence history plot:

  1. Right-click in the convergence history plot and select Save Picture.

    The Image File dialog box appears.

  2. In the Image File dialog box, select a location to which to export the image.

  3. Under File name, enter the name for the file.

  4. Under File type, select the format to export.

  5. Click Save.

1.2.3.4. Exporting Plot Variables and Coordinates

Variables and coordinates from any plot monitor can be exported. Exported files are formatted with comma-delimited entries. This data can be used as the basis for import to another application.

  1. Right-click in the convergence history plot and select Export Plot Variables or Export Plot Coordinates.

    The Export dialog box appears.

    Export Plot Variables exports the monitor data for the variables used in the plot. Export Plot Coordinates exports the actual x/y coordinates used for the plots. These will be different for plots that show coefficient loop data, Cyclic XY plots, and Polar plots.

  2. Under File name, enter the name for the file to which to export the data.

  3. Under Files of type, select the format to export.

    Files are saved with a .csv extension by default, but this can be modified as required.

  4. Under Export Options:

    • Choose a Null Token to be written where a data value is not available (for example, a point where the plot variable is not defined).

      The options are NAN and (empty). The (empty) option means that nothing is written where the data value would normally be output.

    • If a single plot line is broken into multiple sections (for example, for each cycle of a cyclic plot) then, when the values are exported, the data for each section can be separated. Set Line Breaks to indicate what should be written to the file between the plot line sections.

      The options are Null Tokens, Blank Line, No Break. The Null Tokens option writes a line in the same form as the ordinary data values, but using the specified Null Token instead of a numeric value, for all values.

    If the data file is intended to be read into CFD-Post, set Null Token to NAN and Line Breaks to Null Tokens.

    If the data file is intended to be read into Microsoft Excel, set Null Token to (empty) and Line Breaks to Blank Line.

  5. Click Save.

    The data from each plotted variable is exported to the specified file.


Note:  Monitor data can also be exported using the command-line application cfx5mondata.



Note:  You can change which plot line variables are selected by using the Monitor Properties dialog box (right-click in the plot area and select Monitor Properties from the shortcut menu).


1.2.3.5. Exporting Monitor Data from the Command Line

The cfx5mondata application provides a command-line driven mechanism to query or extract monitor data from the directory in which a solver run is executing, a CFX-Solver Results file, or a monitor file. When extracted, monitor data are written in a comma-separated format that is similar to the output generated by the Exporting Plot Data capability.

To obtain a complete list of available command line options for cfx5mondata type the following command into a UNIX terminal or a suitable Windows command line and press Return or Enter:

cfx5mondata -help