Detect Vortex Cores

Use the Vortex Core tool to identify regions in the flow where vortices exist.

The algorithm works by interrogating the velocity field to identify local regions of rotating flow then displaying the center of rotation as a line. These line segments can be visually inspected to identify large scale vortex structures within the flow. For transient cases, tracking the motion and interaction of the vortex cores provides some indication of the local acoustic properties of the flow.
Note: This calculation can be expensive for large models.
A couple notes regarding vortex cores:
  • Vortex cores are computed in the volume based on a chosen vector field. It is the your responsibility to ensure that the vector field is appropriate for the vortex core calculation. For example, AcuSolve writes some vector fields that are all zeros in the volume and only non-zero on the surface (such as wall shear stress). These fields are invalid for vortex core calculation.
  • Vortex cores are intended for use with the velocity field. They are typically computed based on the instantaneous velocity, but time average and running average velocity fields can also be used.
  1. From the Post ribbon, Clips tool group, click the Vortex Core tool.

    Figure 1.
  2. Select solid volumes on which to detect vortex cores.
  3. Click Vector Variable on the guide bar then select a source field option in the microdialog.
  4. Click Calculate.
  5. Use the display properties microdialog to adjust the visualization of the vortex cores.

    Figure 2.
  6. Optional: Toggle Threshold and select a type.
    Applying a threshold to the vortex core helps to eliminate smaller, less important vortex core lines for a clearer visualization.
    Vorticity magnitude
    Normalized vorticity magnitude. Value of vorticity magnitude / maximum vorticity magnitude for the calculated vortex core entity.
    Vortex core length
    Normalized vortex core length. Value of vortex core length / maximum vortex core length for the calculated vortex core entity.
  7. On the guide bar, click one of the following:
    • - Save changes and remain in the tool
    • - Save changes and exit the tool
Restriction: Vortex cores cannot currently be hidden with clips.