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Tecplot 360 2013 Non Zero Velocity at the Wall with FLUENT data

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Old   July 24, 2014, 16:14
Default Tecplot 360 2013 Non Zero Velocity at the Wall with FLUENT data
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Hi Tecplot users!

This is my first post

Recently I decided to try and use Tecplot for post-processing Fluent data instead of the CFD Post Processor from Ansys.

However, when I load my Fluent .cas and .dat files using the Fluent data loader I get a non zero velocity at the walls of my domain. This is of course not physical due to the no slip condition. My guess is that Tecplot uses the data at the grid node adjacent to the wall.

If I plot the velocity at the wall using CFD Post from I get a zero velocity at the wall.

Has anyone else experienced this, and know of any solutions?

Kind Regards
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Old   July 25, 2014, 18:39
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Scott Rumage
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This is a known issue as Fluent data files store their information at the cell centers, and Tecplot 360 plots from nodal values. Tecplot 360 reads Fluent's cell-centered information and extrapolates to the nodal locations. This extrapolation process yields a non-zero velocity at a surface for Fluent data.

One can eliminate this issue if the export from Fluent is specified as nodal (not cell-centered). The specification of cell or nodal values can be made in Fluent’s CGNS data export. Information stored at the nodes will show will show a zero velocity at the wall in Tecplot 360.

Scott
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Old   July 26, 2014, 13:49
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Hi Scott,

Thank you for the answer.

I tried doing as you suggest, but when I import the CGNS file with the node centered data all variables have the value zero in the entire domain.

I also tried using "Specify Equation" in Tecplot to assign zero velocity to all the velocity components at the wall. Now if I make a contour plot of the velocity magnitue on the wall I get a value of zero everywhere.

However, if I make a vector plot of a slice plane, Tecplot still draw velocity vectors at the wall nodes.

Is there any way to circumvent this? I have attached an image to illustrate the situation.

Regards
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File Type: jpg TecplotPic.jpg (55.8 KB, 16 views)
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Old   July 28, 2014, 18:11
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Sorry that I wasn't of much help. I don't have any suggestions other than to double check that the CGNS export file from Fluent was specified as having the data at the nodes.

When I did this type of export, I did have zero velocity at the wall and the remaining domain data appear as expected.

Scott
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