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-   -   Ensight cut plane visualization (https://www.cfd-online.com/Forums/ensight/187545-ensight-cut-plane-visualization.html)

HHOS May 9, 2017 08:26

Ensight cut plane visualization
 
Hello,

I want to ask about a problem that I often have when I do some posts with ensight (exported with Ansys Fluent).

Sometimes when I make a cut in order to visualize a certain variable, there are kind of gaps in the cut. See the white areas in the example picture:

https://s30.postimg.org/mwao6t28h/mesh.png

In this precise case, the mesh is a polyhedral mesh, but it also happens with any other meshes, specially when there are hanging nodes.

Sometimes it can be fixed by moving the cut maybe as little as hundredths of a millimeter, but sometimes it is not possible to get rid of it.

Is there any way to solve the issue??

Thanks!

Regards

kevincolburn May 9, 2017 23:44

We did see that with EnSight version 10.0 and before. Which version of EnSight are you using? We've tried to fix some of these issues that were occurring in recent releases of EnSight. If you are using a version of 10.0 or before, I would certainly try the latest 10.1.6(f) to see if those issues were resolved. EnSight does have problems with the hanging nodes, and thus no connectivity to neighbors, and thus inherent gaps in the domain due to the lack of continuity in the elements.

If you are using a new release of EnSight, let take a look at the model in detail, and we can see if there something about this type of structure which we can take into account to help generate a fully closed clip more robustly.

-Kevin

HHOS May 10, 2017 03:55

Hello Kevin!

Thank you for the answer.

The mesh is in the following picture. I hope you can picture how it is structured. It is not easy to see... Fluent puts together many tetrahedral elements into every polyhedral mesh.

https://s2.postimg.org/3sj5q2y8p/poly.png


All I can say is that we solved the problem by moving the plane slightly. We tried using the latest ensight available to download, but the result was the same.

Regards

kevincolburn May 10, 2017 23:06

Would you be able to provide the actual grid file?

HHOS May 19, 2017 11:33

Hello Kevin!

Thank you for the answer.

I am sorry, but that is not possible. Maybe you can generate it. If you have a fluent version, just convert any tetrahedral mesh into a polyhedral mesh.

Anyhow, the improvement shouldn't be just in this case, which might be special, but also in every case where there are hanging nodes (just to clarify it, the polyhedral mesh has no hanging nodes)

Thanks

kevincolburn May 19, 2017 14:34

Certainly the improvements would not be for just your case. However, I have grids that were tetrahedrals converted to polyhedrals with Fluent. They clip just fine in EnSight, with no holes. So, there is something about my example model which is NOT replicating the situation that you have with your grid. Hence the request for your domain/part of the domain. You can use the Clip Box tool to create a new part which encompasses a few layers of elements about your 2d clip location, and save just that volume part to EnSight Format. You can send us just the geometry file written (no variables, and no grid other than just that small volume portion).

-kevin


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