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Old   July 5, 2013, 10:20
Default [TGrid14.5] recover unmeshed faces
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Andrea
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Hello,
I have a problem with the generation on a mesh on TGrid14.5.

I used ANSA to export a .msh file and mesh it with TGrid5.0.6. Everything worked quite smooth. At a certain point, during the "init" of a domain, TGrid tells me that it could not mesh 11 faces, but then it RECOVERS them and manage to mesh them.
Here is what it writes on the log:

Number of Cells Nodes Not Meshed Nodes/Sec
9821058 0 9
11 unmeshed faces after node insertion.
mesh initialized.
11 recovered faces, 0 un-meshed faces.

Now I have to use TGrid14.5. Doing the same operations with this new version, causes the same unmeshed faces, but this time it DOES NOT RECOVER them and it stops there, with that error.
the log is

Number of Cells Nodes Not Meshed Nodes/Sec
9820631 0 10
9 unmeshed faces after node insertion.

Error: Duplicated faces bf2986628 bf2986629

Error Object: #f

mesh init not completed.

0 unmeshed nodes.
bf919632 on zone cri_condotto_aspirazione not meshed.
bf919639 on zone cri_condotto_aspirazione not meshed.
bf2146484 on zone cri_conv_freno3 not meshed.
bf2146502 on zone cri_conv_freno3 not meshed.
bf2318166 on zone crw_brake2.mw not meshed.
bf2401222 on zone crw_brake2.mw not meshed.
bf2986628 on zone cfb_triangoloinf_sosp not meshed.
bf3012914 on zone crb_gruppoinf_sosp not meshed.

8 unmeshed faces, (number reported 8).

mesh init not completed.


I cannot find the right comand to tell TGrid14 to recover those unmeshed faces and move on.
Does anybody know how to do it?
Thanks for any help, it'd be much appreciated!
Andrea
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Old   July 8, 2013, 08:08
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Vangelis Skaperdas
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Not really an answer to your question but it may help.

Have you tried to find the problem in ANSA?
Have you checked the mesh quality?
Have you checked for proximities?

Have you tried a quick tetra mesh in ANSA to see the problem areas?

Vangelis
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Old   July 9, 2013, 04:43
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Thank you for your interest.

Actually, what you suggested to do is what i'm doing right now.
At first, since I was using the very same ANSA.defaults and version of the program, i assumed it wasn't responsible for my problem.

Thanks.

Andrea
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Old   July 9, 2013, 04:55
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Vangelis Skaperdas
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Hello Andrea,

Which ANSA version are you using?
Are you using the CFD startup mode?
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Old   July 9, 2013, 09:07
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Hello,
i'm using Ansa 13.1.2 and i was using ANSA startup mode.
I tried to switch to CFD startup. TGrid is still giving an error, although this time the duplicate faces are different (but thery are still 2) and the zones are also different.
Result is 10 unmeshed faces. Then it stops.
Thanks,
Andrea
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Old   July 9, 2013, 09:25
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Vangelis Skaperdas
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I would like to recommend the following:

1) Always prefer the CFD start up mode of ANSA
as it is tuned to give you best results for CFD pre-processing

2) Upgrade to a newer version as this is a bit old (Feb 2011)
to get the best possible functionality from ANSA

Anyway even in this older version check for

1) Mesh quality in HIDDEN mode (again you should start ANSA in CFD
mode to have pre-defined good quality criteria for CFD)
2) D.UTIL>CHECK>PENETRATION>INTERSECTIONS
3) D.UTIL>CHECK>DUPLICATE
4) D.UTIL>CHECK>PENETRATION>ELEMENT LENGTH to find proximities
5) Check you model in BOUNDS view mode to see if there are gaps or triple connectivity
6) Try VOLUMEs>DEFINE Auto Detect to see what ANSA identifies as closed volumes
7) Try VOLUMEs>MESHV>TetraRapid to see if ANSA can volume mesh

Let me know how it goes
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Old   July 9, 2013, 09:51
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Thank you very much for your help so far.

I'm actually doing my thesis and this is the first time I use such programs, so i'm very un-expert.
Unfortunately I have to make things work with these versions of softwares, as the company i am doing the thesis for has bought such versions.

I will try what you suggested.

I have one more question: since i'm using a specific and given ANSA.defaults (mandatory) , does it make a difference on what kind of startup i launch Ansa?
I mean, does it differ if i launch it with ANSA startup or with CFD since, after that, the program loads the same ANSA.defaults?
Thanks,
Andrea
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Old   July 9, 2013, 10:18
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Vangelis Skaperdas
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Hi Andrea,

If you start ANSA in CFD mode ANSA will read a CFD.defaults file
not an ANSA.defaults file, so you will be using different settings.

I hope the ANSA.defaults settings are suited for CFD work.

Vangelis
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Old   July 11, 2013, 12:48
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Hi vangelis,
thank you for your help.

With the checks you made me do on the original ANSA file, I found that there were duplicated faces. Once I deleted them, TGrid 14.5 went smooth as oil.
It finds 18 "new" unmeshed faces, but then it manages to recover them. I believe that what TGrid calls "unmeshed" faces, are internal faces that don't need to be meshed.

It is weird that the older TGrid didn't give me such error messages, though.
Such behaviour made me think that if there was something wrong, then it had to be on TGrid, and not in ANSA, since it went smooth on the older TGrid version.

Thank you again for helping me!

Andrea
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Old   July 12, 2013, 03:02
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Vangelis Skaperdas
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Glad it worked out for you!
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