Learning Forum

[Christian Berwanger]

Hello,
I would like to visualize pathlines in my CFX simulation. However. In CFD-Post I can only see the option to create streamlines. Importing the result file in Fluent doesn't seem to work either as the Pathline option is greyed out. Is there any option to create pathlines in CFX?

Thanks and Kind regards

[CFD_Friend]

Hi Christian,

Streamlines are lines everywhere tangent to the velocity vector at a given instant

-Pathlines are the actual path traversed by a fluid particle.

 

For steady cases, streamlines and pathlines are identical.  For transient cases, they're not. 

 

To model pathlines in CFD-Post for a transient run, here is one approach:

 

1. In CFD-Post, read in the first timestep.  Create streamlines but use the Limiter option set to the timestep size. Export the streamlines from Post.
2. In an external tool (i.e. Fortran, Python, etc), read in the streamline export file.  Find the endpoints of each streamline.  Generate a Cloud of Points file.
3. In CFD-Post, read in the next time step.  Read in the Cloud of Points from the previous time step.  Create streamlines from these cloud points but use the Limiter option set to the timestep size. Export the new streamlines from Post.

Repeat Step 3 for the remaining time steps.

 

At the end, you will have a set of exported streamline files.  You now may be able to read all those files into CFD-Post to visualize the pathlines