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July 5, 2016, 10:17 |
Meshing problem for transient analysis
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#1 |
Member
Arun subramanian
Join Date: Jun 2016
Location: Florence,Italy
Posts: 48
Rep Power: 10 |
I am trying to make transient analysis for a simplified piston model with single intake and single outlet. I have shown it in picture 1 .
I have a problem with "negative volume " . I know my mesh is very bad . The surface mesh is pretty good to look from outside but inside using section plane ,it looks very bad as in pic 2. How do I make a hexagonal mesh which are same in size ? Is it possible that I can "extrude " mesh from the base till the top ? What are best practices to make hexa mesh ? Also is there a comprehensive tutorial/PDF to read for transient analysis ? Probably there are a lot of posts on this but I have less time now to search all. It will be nice to get specific answer for my problem. Cheers, Arun |
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July 5, 2016, 10:59 |
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#2 |
New Member
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I think your question must be in meshing forum:
http://www.cfd-online.com/Forums/ansys-meshing/ maybe you need to review some of examples and always the point is not to have a 'hexagonal mesh which are same in size'...You must be aware of how to evaluate your grid structure and check it. some Properties of mesh you should check: Skewness boundary layer mesh (Inflation) angels growth rate ... |
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July 5, 2016, 11:39 |
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#3 |
Member
Arun subramanian
Join Date: Jun 2016
Location: Florence,Italy
Posts: 48
Rep Power: 10 |
Hello !
thanks for your reply. Can I know how should these parameters look like so that I get correct mesh? rather what are optimum values? |
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July 5, 2016, 19:53 |
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#4 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,864
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Your mesh is really bad and it is never going to work like that. I recommend you do the meshing tutorials to find out the basics of meshing.
In this case as you have a cylindrical object (which I presume is the piston) with some ports attached, I recommend you: 1) Separate the ports and cylinder. Mesh them separately. You should then get a very good mesh for the cylinder as it will just be a simple sweep mesh. 2) Connect them up using GGI interfaces. As they are going to move they will need to be Transient Rotor-Stator. 3) The ports can be stationary mesh, the cylinder moving mesh. 4) As the cylinder is just a simple linear squashing of the mesh the mesh motion stuff should work well on this. If you need some help, have a look at the FAQ: http://www.cfd-online.com/Wiki/Ansys..._went_wrong.3F |
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July 6, 2016, 05:38 |
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#5 |
Member
Arun subramanian
Join Date: Jun 2016
Location: Florence,Italy
Posts: 48
Rep Power: 10 |
Thank you very much for the reply ! One quick question... where can I find the tutrials?
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July 6, 2016, 06:54 |
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#6 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,864
Rep Power: 144 |
The ANSYS Community web page.
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Tags |
cfx, mesh, transient analysis, transient tutorials |
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