Hello all,

I want to show the vortex rope or vortex in CFX Post 5.7. Can anyone tell me how to do that? I can't find the variable "helicity " in the post. Can we calculate this value and create a iso-surface for this? Please kindly advise me. THank you very much, leslie

Hi,

You can calculate it as an additional variable either in the solver or in CFX-Post and view it that way.

Glenn Horrocks

Hi Glenn,

Thank you. Will look at this option. Is there any vortex-core tracking algorithm in CFX Post? Streamline doesn't provide good visualisation for this purpose anyway.

Regards, Leslie

Hi,

CFX has no built in vortex tracking. In fact vortex tracking in 3D flows is an area of current research and there is no simple way of doing it. Things you can try include scalar speed, pressure or vorticity - sometimes these simple variables can give a useful indication of where the vortex cores lie. However, in general you will need a more sophistocated approach.

Glenn Horrocks

Fieldview can do this. Fieldview also allows for vector operations on you data (easy calculation of vorticity for instance). We still use filedview next to post (mostly because post used to be very bad, but is certainly improving now)

Hi Bart,

Thank you. We do have FieldView but it's a very old version. Which version are you using right now? What about techplot?

I just need to export the pressure/velocity/ etc data for the whole fluid domain from post and then import to Fieldview or Techplot for processing, right?

I did find some literature about the vortex tracking algorithm but it's quite complex & time-consuming to write my own. Does anyone have a free code to track the vortex?

Thanks, Leslie

yes you have to export to fieldview (using cfx5export -fv .....). No such thing for tecplot however (user defined export needed for that). We use Fieldview 9 (I think 10 is available but we haven't used it yet). Haven't used tecplot in a long time but it should be possible to do it in Tecplot