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-   -   [ICEM] ICEM CFD Penetrating Elements/Surface Orientation Issues (http://www.cfd-online.com/Forums/ansys-meshing/79960-icem-cfd-penetrating-elements-surface-orientation-issues.html)

GSbert September 9, 2010 11:09

ICEM CFD Penetrating Elements/Surface Orientation Issues
 
Hello,

I am doing some mesh manipulation in ICEM, and ran a mesh check after changes were made to the mesh. The mesh check uncovered both penetrating elements and surface orientation issues. I am not sure how to repair these elements even after reading some of the help documentation. Any guidance would be appreciated.

BrolY September 9, 2010 11:50

Localize those elements, and look at your mesh around this area.

Did you create and tetra mesh or an hexa mesh?
If it is a tetra mesh, it may be the mesh which have not well captured the geometry.
If it is an hexa mesh, modify your blocking.

Maybe you should had some pictures and information about the changes you made. Or even attached the full model.

PSYMN September 21, 2010 16:40

Visuals help
 
Yes, mesh problems are not easy to diagnose with a single sentence and no visuals...

harman79 May 11, 2011 13:15

Penetrating Elements Problem
 
2 Attachment(s)
Hi all,

I wanted to mesh a 3D model of a vacuum generator and due to the complexity of the design I decided to mesh it in bits and pieces.. What I did, was to use the original 3D CAD model in ACIS format, each time picking the geometry of a simple volume, deleting the rest. I thought that this way, the coordinates would basically remain intact.

Unfortunately upon assembly of the meshed volumes I ended up with a considerable number of penetrating elements, probably originated from slight variations of blocking stategy at the joining areas/surfaces.

I have added a picture highlighting the problem... Is there anyway of deleting these penetrating elements (i.e. upon subsetting them) and then filling the "holes" without having to go back to blocking phase???

Thanks a lot for your time,
Harry

jeevankumarb May 12, 2011 04:05

Your images doesnt give much information on where the problem is. it will good if you can post images of your blocking. It will be better if you can upload your blocking and the geometry file so that i can look at the blocking and see where the problem.

Regards

PSYMN May 12, 2011 09:22

Imprint
 
Yea, I couldn't really tell from those images either...

However, if you were planning on non conformal interfaces you missed a step.

Lets say you had a small cylinder up against a larger one. When you mesh the small cylinder, its entire face can be part of the interface (so no problem), but when you mesh the larger one, you need to separate the surface into the outer wall region and the inner interface circle. To do this, you need to keep the curve "imprint" of the smaller cylinder on the face of the larger cylinder, then make sure that your blocking includes edges along that smaller cylinder (just split your Ogrid and associate to the curve).

This will probably sort out your penetration problems also.

It may not help you, but if I were doing this model, I would probably just create one blocking for the whole thing, it is mostly just concentric cylinders... Or maybe just do the axial portion as one bigger model and then do the 90Degree piece separately. Fewer interfaces will increase your accuracy. But maybe your skill level is just not quite there yet and this is a good compromise for you.

harman79 May 12, 2011 12:57

Guys,

thanks a lot for your replies and for your interest.

I have added the model geometry, blocking and mesh in this link:

https://rapidshare.com/files/868748459/Mesh_Model.rar

(hopefully the link works...)

I deleted all penetrating elements and fixed walls that were actually getting in the middle of the flow (e.g. what simon said wrt to curve imprints etc) but ended up with uncovered faces. When I added an extra part for the uncovered faces then I ended up again with penetrating elements :)... vicious circle there...

Note that for the project included in this link, the blocking has been "extracted" using the
Load -> Blocking -> from unstruct mech
command

This was to avoid adding 10 or so block files and keep things simple :)

If each separate file is a must, then I would gladly send those too.

Simon, I have tried to follow the single block route but it was too much for me...

Thanks a lot again
Harry

hhh August 10, 2012 04:48

Project the surface in ICEM CFD
 
Dear friends,
i am new to ICEM CFD, in that i draw Rectangular surface, i want to project in z direction, i dont how to project, please let me know

nitinbansal184 August 13, 2012 05:03

Quote:

Originally Posted by hhh (Post 376397)
Dear friends,
i am new to ICEM CFD, in that i draw Rectangular surface, i want to project in z direction, i dont how to project, please let me know

Go to surface select sweep surface then select required curves and driving curves

nitinbansal184 August 13, 2012 05:04

Quote:

Originally Posted by harman79 (Post 307395)
Guys,

thanks a lot for your replies and for your interest.

I have added the model geometry, blocking and mesh in this link:

https://rapidshare.com/files/868748459/Mesh_Model.rar

(hopefully the link works...)

I deleted all penetrating elements and fixed walls that were actually getting in the middle of the flow (e.g. what simon said wrt to curve imprints etc) but ended up with uncovered faces. When I added an extra part for the uncovered faces then I ended up again with penetrating elements :)... vicious circle there...

Note that for the project included in this link, the blocking has been "extracted" using the
Load -> Blocking -> from unstruct mech
command

This was to avoid adding 10 or so block files and keep things simple :)

If each separate file is a must, then I would gladly send those too.

Simon, I have tried to follow the single block route but it was too much for me...

Thanks a lot again
Harry

The link doesnt work.....use 4shared(DOT)com for file storage


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