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Post-Processing -> Interpolation of cell-centered values to vertex

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Old   June 26, 2010, 14:02
Default Post-Processing -> Interpolation of cell-centered values to vertex
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Hi,

I am using Tecplot as a post-processor to visualize CFD-solutions which are stored within an _unstructured CGNS_ (cell-centered). Loading the CGNS-file into Tecplot, I noticed that contour-plots of (all) quantities like mach-number etc. are not smooth. (The simulation converged very nicely. Therefore, I believe that it is only a visualization-problem).

1. Could this be a Tecplot-interpolation-problem? Are there fixes available??
2. I thought that the problem might be the data-storage within the CGNS. Maybe the contours become smooth if I transfered the data from the nodes (=cell centeres) to the vertexes???

Has anybody experience with this issue??? Are there free tools available to interpolate the solution from the nodes to the vertexes???

Thanks in advance.
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Old   June 26, 2010, 16:09
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There is a simple methodology to interpolate the data from the cells adjacent to one node: use the inverse of the distances as weights. You can search for the articles of Neal T Frink:

http://aaac.larc.nasa.gov/tsab/cfdla...ssertation.pdf

Page 17 formula 3.10

Hope this will help.

Do
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Old   June 26, 2010, 23:54
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Quote:
Originally Posted by DoHander View Post
There is a simple methodology to interpolate the data from the cells adjacent to one node: use the inverse of the distances as weights. You can search for the articles of Neal T Frink:

http://aaac.larc.nasa.gov/tsab/cfdla...ssertation.pdf

Page 17 formula 3.10

Hope this will help.

Do
You will lose accuracy by doing that. You must do atleast linearly-consistent (exact for degree-one polynomials) interpolation (Frink proposes a way to do that). It should be possible within tecplot but I have never done it. You might getter advice by posting on a tecplot forum, see

http://www.tecplottalk.com/
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