Post-Processing: Examining Velocity Vectors

For simulations involving fluid flow, you almost always want to view the flow movement as it passes through the flow domain. Vector scenes are a common technique for viewing flow movement. In this example, using the final simulation file from the Introductory tutorial, you set up vectors in a reflected symmetry plane around a solid-colored blunt body.

To prepare for this tutorial:
  1. From the tutorials bundle, within the introduction folder, copy Introduction_final.sim to your working directory. Alternatively, work through the Introductory tutorial and start from the final simulation file.

    See Downloading the Tutorial Files from the Support Center Portal.

  2. Open Introduction_final.sim (or your own version from the Introductory tutorial), and save it as velocityVectors.sim.
To set up the vector scene:
  1. Right-click the Scenes node and select New > Vector.
  2. You do not need the outlines that the Outline 1 part displayer provides by default, so reuse that displayer to show the blunt body as a solid object.
    1. In the Scene/Plot tab, select the Vector Scene 1 > Outline 1 > Parts node and click (Custom Editor) in the Parts property.
    2. In the Parts dialog, to remove any initial selections, click the (Select All) button twice.
    3. Expand the Regions > subdomain-1 > Boundaries node.
    4. Select the Inner_wall node.
    5. Click OK.
    6. Select the Outline 1 node and make the following changes to the Outline 1 displayer properties:
      1. Deactivate the Outline property.
      2. Activate the Surface property.
      3. Set the Transform property to Symmetry_plane2 1.
When you create a vector scene, the default setup is for the Vector 1 displayer to show the Velocity vector field. Here, you retain this field, but must make some adjustments to show vectors on the desired plane.
  1. To set up the plane on which vectors are rendered, do the following:
    1. Select the Vector 1 > Parts node and click (Custom Editor).
    2. In the Parts dialog, select the Regions > subdomain-1 > Boundaries > Symmetry_plane1 node, then click OK.
    3. To highlight large differences in velocity effectively, within the Vector 1 node, select Color Bar and set Color Map to purple-red basic (large difference).
    4. Select the Vector 1 node and set Transform to Symmetry_plane2 1.

    These settings show a solid blunt body with velocity vectors surrounding it.



    It is possible to make the arrows shorter to see the vectors more clearly.

  2. Select the Vector 1 > Glyph > Relative Length node and change Glyph Length (%) to 2.0.

    The arrows now appear shorter.



  3. Save the simulation.