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-   -   CFX Post - Vector field lines possible? (http://www.cfd-online.com/Forums/cfx/92418-cfx-post-vector-field-lines-possible.html)

tdpomodoro September 13, 2011 23:32

CFX Post - Vector field lines possible?
 
Hi guys,

Been reading the forum for a long time - lots of knowledge here.

I've come across a problem that's stumped me. I'm trying to create a vector plot to visualize the swirling nature of the fluid downstream of a cylinder.

I'd like the arrows joined head to tail, sort of like a an isobar but for velocity?

I've searched through the ANSYS help files to no avail, it seems all that is possible is a field of vectors.

Any help would be much appreciated.

Here's a picture of what i'm trying to achieve:

http://home.exetel.com.au/saladdays/...ctor-field.jpg

Lance September 14, 2011 02:31

Um, one way could be to first create stream lines and then create a vector field where you specify location: streamline 1 in the settings for the vector plot. Would that give you what you want?

ghorrocks September 14, 2011 07:07

Another option could be to define the cross section planes then do surface streamlines on the planes.

tdpomodoro September 14, 2011 10:33

Thanks for your replies, guys.

Quote:

Originally Posted by Lance (Post 324041)
Um, one way could be to first create stream lines and then create a vector field where you specify location: streamline 1 in the settings for the vector plot. Would that give you what you want?

Lance, I just gave that a try. Novel idea however I couldn't get it working.

Quote:

Originally Posted by ghorrocks
Another option could be to define the cross section planes then do surface streamlines on the planes.

Glenn, I had a play around and I came to that conclusion as well however the results aren't as elegant as in the screenshot I put up previously.

Also, when I apply an arrowhead to the stream lines they point normal to the plane?

Perhaps these surface streamlines aren't actually giving me the vectors in the plane of the plane?

http://home.exetel.com.au/saladdays/...streamline.jpg

brunoc September 14, 2011 17:24

Glenn's suggestion should work. Try playing with the min and max times and the interval. Use a constant black color. Also, instead of using the arrowhead, use arrowhead 3D and disable lightning at the render tab. That should give you something close to what you want.

Sal September 15, 2011 06:52

Unfortunately, arrows will never be as good as these ones shown in your Fig.6. As far as I am aware, Glenn & brunoc's suggestions are the only available approaches in CFD-Post (at the moment) to solve this issue.
FYI, you can change projection to Tangential on Vector Plot but results are still not as good as those.
Alternatively, you can draw Surface Streamlines on specific cross-section planes (see Glenn thread) without any symbols, and then add 'arrows' using any image editor software.
Hope it helps.


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