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October 19, 2010, 22:28 |
Poitwise and Fluent, non positive elements
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#1 |
New Member
Filip Wallberg
Join Date: Oct 2010
Posts: 23
Rep Power: 15 |
Hi to you all.
Im am trying to learn how to use Pointwise in combination with Fluent. I have worked through all tutorials that comes with Pointwise and have successfully managed to export the mesh, so far so good. The problems start when i try to read the cas file in Fluent, the grid check tells me that i have non positive elements. So im assuming that something is wrong with my mesh. How should I go about correcting this? (The mesh i have been playing around with is the "2d airfoil" case which is the first tutorial that comes with Pointwise) |
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October 20, 2010, 20:32 |
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#2 |
New Member
Xu Zhu
Join Date: Oct 2010
Posts: 12
Rep Power: 15 |
what version of pointwise gridgen are your using?
if your reply me and i didn't know for a long time, please email: lachie.zhu@gmail.com and let me know. |
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October 20, 2010, 23:42 |
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#3 | |
New Member
Filip Wallberg
Join Date: Oct 2010
Posts: 23
Rep Power: 15 |
Quote:
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October 21, 2010, 00:57 |
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#4 |
New Member
Xu Zhu
Join Date: Oct 2010
Posts: 12
Rep Power: 15 |
that's it. my version is also V16.02R3, i have be confused by this problem for a long time. then i solved it.
if you generate a 2D grid, the software seems more tend to give you a negative area than 3D. when you fish the grid, choose all the domain, click the "edit" on the Menu Bars,choose the "orient", click "I" or "J", then "apply". done i am a freshbird, i don't know why the problem can be solved if i do so, certainly, the grid must not be too bad. i also want the expert of pointwise to give me more details about this. hope helps. |
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October 21, 2010, 04:13 |
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#5 | |
New Member
Filip Wallberg
Join Date: Oct 2010
Posts: 23
Rep Power: 15 |
Quote:
would be good to know the reason for this though |
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October 21, 2010, 05:07 |
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#6 |
Member
ganesh
Join Date: Mar 2009
Posts: 40
Rep Power: 17 |
Dear Friends,
I had faced the same problem and solved it in a similar way, what I find by comparing the .cas files from Gridgen and that for the same mesh from GAMBIT are that the normals are differently oriented. The flip that was suggested essentially gets the .cas file from Pointwise to be consistent to what GAMBIT would have provided. Regards, Ganesh |
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October 27, 2010, 09:44 |
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#7 |
New Member
Yang Jing
Join Date: Oct 2010
Posts: 2
Rep Power: 0 |
i have the same problem in 2d case.and now i know how to fix it. all my thanks
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October 29, 2010, 03:01 |
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#8 |
New Member
Xu Zhu
Join Date: Oct 2010
Posts: 12
Rep Power: 15 |
hi guys:
i think i have made more clear of this problem. i found an official explanation in the user manual of the Pointwise V 16.02. On the page 4.34, you can see "For 2D and 3D structured domains and blocks, the orientation can be changed with the commands in the Reverse and/or Swap frames. NOTE THAT THE GOAL FOR orienting structured domains and blocks for most cases is to make them RIGHT-HANDED. For 2D and 3D unstructured domains and blocks, the Reverse Normal command will flip the domains or block face normals in the opposite direction. For an unstructured block, it is desirable for the normals to point toward the interior of the block. " So, if you build a multi block like me(2D), as you see in the picture, what you should do is to make ALL the domain RIGHT-HANDED. For more details, you can see the manual yourselves. |
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November 1, 2010, 04:04 |
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#9 | |
New Member
Filip Wallberg
Join Date: Oct 2010
Posts: 23
Rep Power: 15 |
Quote:
How do you actually see if the grid is RIGHT HANDED? When i click the Reverse - Normal button there are now arrows or anything indicating in which direction the normals are oriented. |
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November 1, 2010, 09:37 |
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#10 | |
New Member
Xu Zhu
Join Date: Oct 2010
Posts: 12
Rep Power: 15 |
Quote:
first, if you do not know what is RIGHT HANDED exactly, you should review it in the math book. second, when you in the ORIENT label of 2D STRUCTURED grid, you will see the domain you have choosed has connectors of two different colord, one stands for I, and the other J. what you should do is to make the position relationship between I and J like the one between X and Y in the globe coordinates. (I = X, J = Y) In the multi block strctured grid generation this makes sense, and in the unstuctured one it can be more easier. holp helps. |
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November 2, 2010, 11:40 |
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#11 | |
New Member
Filip Wallberg
Join Date: Oct 2010
Posts: 23
Rep Power: 15 |
Quote:
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