Surface lines for CGNS?

Moderators: davetaflin, salter, steve, jprenaud, straton, Chris Idso

akiss20
Experienced user
Posts: 10
Joined: Mon Nov 25, 2013 7:34 am
Location: Cambridge, MA

Surface lines for CGNS?

Postby akiss20 » Tue Dec 03, 2013 6:34 am

Hello All,

I am wondering if anyone knows how to specify the parent for a surface subzone in CGNS? My CGNS file has an O mesh around a single rotor blade on which I want to plot surface lines to visualize the extent of the TE separation. I make a surface subzone from the I=1 plane of the O-mesh zone which is the blade surface and then set that as a wall BC in the Geometry and Boundaries dialog box. I can place surface lines but I do not think they are accurate as they show no separation whatsoever (and I know there is a significant amount of hub separation which I see in the flow solution). I was reading the manual and saw the section on page 246 about needing a parent zone for the surface zone for the surface lines to work. It only mentions setting parent zones for ASCII data. How can this be done for CGNS data? I can't believe that surface lines can only be plotted for ASCII data and not for the 10,000 other possible formats.

Thanks

akiss20
Experienced user
Posts: 10
Joined: Mon Nov 25, 2013 7:34 am
Location: Cambridge, MA

Re: Surface lines for CGNS?

Postby akiss20 » Fri Dec 06, 2013 8:37 am

I got it, but it is a clunky solution. I took the advice of scottf in (http://tecplottalk.com/bb/viewtopic.php ... db665345a4). Because I have a blade O mesh it was relatively straightforward. I created a subzone with the first two I planes of the blade O mesh (the blade surface and the first plane above it) and one with just the blade surface and exported as ASCII. I went into the ASCII file, added the auxdata and parentzone header to the just blade surface zone and then re-imported the zones in tecplot. I could then create surface streamlines on the imported blade surface zone as it had the volume subzone containing the first two I planes of the blade O mesh as a parent zone.

That being said, this is a really annoying way of having to do what I would have thought was a common thing. It first of all takes up hard disk space (granted my mesh isn't that big so the exported ASCII files are about 15 MB or so and I only exported the variables Tecplot needs to define the wall shear stress, but for finer meshes that could get bigger) but worse it is impossible to automate as it requires editing of the ASCII files. I suppose one could write some kind of bash script or python script or something to perform some regex on the exported ASCII, but still.

Tecplot, this seems like it should be a pretty easy thing to fix. Can you not create a way to assign parent zones from within the GUI/scripting language?

Thanks

scottf
Tecplot Employee
Posts: 115
Joined: Wed Apr 05, 2006 8:58 am
Location: Bellevue, WA
Contact:

Re: Surface lines for CGNS?

Postby scottf » Mon Dec 09, 2013 11:59 am

akiss20,

You can edit auxiliary data directly via the "Data->Auxiliary Data..." dialog. You can also automate this by using the $!SETAUXDATA macro command.

Using either of these methods you should be able to avoid writing data out to ASCII.

Scott
Scott Fowler
Image

akiss20
Experienced user
Posts: 10
Joined: Mon Nov 25, 2013 7:34 am
Location: Cambridge, MA

Re: Surface lines for CGNS?

Postby akiss20 » Mon Dec 09, 2013 12:00 pm

Hi Scott,

I know I can set Aux data using the scripting, but is the PARENTZONE header considered aux data? Can that be set via scripting?


Return to “Tecplot 360 and Focus”

Who is online

Users browsing this forum: No registered users and 1 guest