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-   -   Post processing slice files for periodic pipe flow (https://www.cfd-online.com/Forums/tecplot/145771-post-processing-slice-files-periodic-pipe-flow.html)

Dan1788 December 11, 2014 21:15
Post processing slice files for periodic pipe flow
 
Hello,

I am doing an LES of a pipe flow using OpenFoam 2.2.x . My question is that whenever I look at contours on slices, the "start/end slice" in the "show derived objects -> slices" is always a few units away from the actual inlet/outlet, as shown in this figure. Why is this so ??

https://copy.com/VoWydn9M9XbGyYTM

Where as when I drag the slice to the actual "inlet" and "outlet" location, it looks like this:

https://copy.com/uNaj422sKqDSSme1

Shouldnt the inlet and outlet be a colored contour like the mid-slice ??

I ask this because after my LES of pipe simulation, I will map the turbulence at my outlet to the outlet of a jet for a reacting flow calculation and I want the actual turbulence, not the one that shows up in the figure above.

Is this just a graphical issue or is there something wrong with the calculation? Would be really grateful if anyone could let me know. Thanks!

Durrell4 December 12, 2014 16:02
Probe the inlet and outlet using the probe tool to confirm the data are correct
 
Hi Dan,

If you use the probe tool and probe the inlet and outlet do the values of W correspond to what is shown in the second image in you post? My guess is that the contours on the inlet and outlet are accurately being colored.

I could take a look if you upload the data to ftp://ftp.tecplot.com/misc/ and see if I can trouble shoot the results. Are you loading the data using the OpenFOAM loader or are you converting to Tecplot via OpenFOAM to create a *.plt file.

Let me know what you learn and I can see if I can help.

Best

Durrell

Dan1788 December 13, 2014 00:45
Hi Durrell,

Thanks so much for your reply. As you asked, I checked the velocities using the "probe" tool at the end of the pipe and the results are consistent with mid-slices. Following are the velocities at 5 locations I checked:

Code:
(x y z)                  (Ux Uy Uz)
(0 0 0.075)              (0.717598 -0.302497 12.6124)           
(0 0.001 0.075)          (0.778587 -0.404296 11.4304)           
(0 0.002 0.075)          (-0.287753 -0.381464 10.5165)           
(0 0.003 0.075)          (-0.568692 -0.21863 9.04931)           
(0 0.004 0.075)          (0.164574 -0.621398 9.49656)           
(0 0.005 0.075)          (0.565432 -0.716736 10.5363)
I did the same test to the channel395 tutorial which is already available on OpenFoam. When I look at the slice contour it appears to be something like this:

https://copy.com/lu4pjP1tcMHpm80B

Please let me know why this is ? Also how do I upload my data to the link you gave me ? Thanks :)

Durrell4 December 16, 2014 19:26
Uploading files
 
Hi Dan,

ftp://ftp.tecplot.com/misc/ can be opened in a web browser or just use "FileZilla" and connect to ftp.tecplot.com

As soon as the files are there I will see if I can nail down the issue.

Durrell


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