Defining the Dependent Variables

In an XY plot, each dependent variable is defined as a Y Type, regardless of where its axis appears.

To create and define a dependent variable (by default, one is already present):
  1. Right-click Plots > [xy plot] > Y Types and choose New.
    • Alternatively, right-click the destination axis in the plot display, or the node of that axis under the Axes node, and select Create new referencing Y type.
  2. If you want to plot this quantity against its own axis, right-click [xy plot] > Axes and choose New Axis followed by Right or Top (assuming that Bottom and Left already exist).
  3. Select the [Y type] node and change Y-Axis if necessary.
When plotting data, Simcenter STAR-CCM+ can either show the raw computed data as it appears along the direction of interest, or it can interpolate the data.
  1. To plot interpolated data, activate Smooth Values.
    The smooth plot is generated using vertex values rather than cell centroid-based values and appears smoother than the default style. However, for most scalar fields vertex values are interpolated from cell values, and thus data extraction with the smooth-filled option is more expensive in terms of computing power.
  2. To choose the quantity for plotting, select [Y type] > Scalar Function and set Field Function to an item from the list.
  3. To adjust the data range for the associated axis, select Axes > [associated axis] and modify the properties until you are satisfied with the range shown on the plot. For details, see [Cartesian] Axis Properties.
  4. With the right settings, a line-probe can help you plot results, such as heat transfer, in a line on a planar boundary. To do this:
    1. With a scene open, create a line probe. See Defining a Line Probe.
    2. Select a planar boundary as the input part.
    3. Activate the Snap to Part option.
      This option attaches the line to the selected surface.
    4. Create an XY plot and select the line-probe in the Parts property.

Plotting the Velocity Profile Across a Pipe Flow

A common plot in pipe flow simulations is the velocity profile. Plotting this profile in Simcenter STAR-CCM+ requires that you first create a line probe derived part, and then refer to that part in a separate XY plot.

The following steps describe an example workflow of how to visualize a scalar velocity profile through a section of a pipe flow:

  1. Create a 2D plane section across the width of the pipe flow geometry, parallel to the inlet and outlet part surfaces.

    Although this step is not crucial, it makes sure that the line probe lies along a surface that is parallel with the outlet. See Defining a Plane Section.

  2. Create a 1D line probe across the diameter of the plane section. To make sure that the line probe is created precisely through the diameter of the plane section, in the Create Line Probe in-place dialog:

    1. Activate Snap to Part.
    2. To the right of the Snap to Part option, click (Custom Editor).
    3. In the Select Object dialog, select the Derived Parts > [Plane Section] part and click OK.
  3. Click Create, then Close.

Each point in the line probe represents the location from which data is gathered. The number of points in the line probe represents the number of plots which appear on an XY plot.

  1. To increase the number of points across the line probe, select the Derived Parts > Line Probe node and set Resolution to a higher value.
  2. Create an XY plot. Right-click the Plots node and select New Plot > XY Plot.

  3. Expand the XY Plot 1 node and set the properties that you require. For example:

    Node Property Setting
    XY Plot 1 Parts Derived Parts > Line Probe
    X-Type
    Vector Quantity Value Set the X, Y, or Z coordinate to represent the direction of the line probe. Typically you set one of these coordinate directions to 1.0.
    Y Types
    Y Type 1 Smooth Values When this option is activated, the X-Y plot appears as a smooth curve as the line probe linearly interpolates from values that are located at the vertices of the region or boundary. These values are computed by averaging cell centre values from neighboring cells (when solving using a finite-volume method).

    If this option is deactivated, nearest cell centre values are used – which the solver produces directly – and the X-Y plot appears stepped, not smooth.

    Line Probe
    Line Style Style Select one
    Scalar Function Field Function Velocity > Magnitude
  4. Open the XY plot in the Graphics window.
    Note Modifying derived parts or X-Y plots does not modify the mesh that the solution uses. Therefore, you do not need to rerun mesh operations or solvers.

The following image shows the scalar velocity magnitude on an XY plot which uses data that is taken from the line probe with Smooth Values activated.