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-   -   [GAMBIT] complex geometry meshing (http://www.cfd-online.com/Forums/ansys-meshing/65051-complex-geometry-meshing.html)

1682333 June 2, 2009 10:30

complex geometry meshing
 
enclosed is a PDC bit used in petroleum engineering. Does anyone here deal with such a problem before?
I tried and tried and just can't mesh the geometry correctly.
The continuum is a 200(radius)*200(height) cylinder with the PDC subtracted from it.
In order to get the continuum, you should translate the cylinder -170 unit in Z direction.

http://rapidshare.com/files/239994767/358-tmp4.zip.html

Thank you in advance.
John.

sakthivel August 11, 2009 07:32

Heat exchanger design
 
I am designing the heat exchanger and analysing using GAMBIT AND FLUENT SOFTWARES....... I need the details for fluent specification... can you help me..

1682333 August 23, 2009 04:48

Here is whta I am doing:
analyze the problem-write journal files-start gambit or fluent-read journal files.
refer to users' guide for information about the journal file specifications.

gocarts August 25, 2009 11:24

Small Edges and Sliver Faces
 
1 Attachment(s)
I looked at your geometry in a pre-release of SymLab v2 and found some small edges and sliver faces that might be causing Gambit problems.

In SymLab v2 I was able to produce a tetrahedral mesh and solve using OpenFOAM, see attached picture.

1682333 August 30, 2009 08:32

Quote:

Originally Posted by gocarts (Post 227452)
I looked at your geometry in a pre-release of SymLab v2 and found some small edges and sliver faces that might be causing Gambit problems.

In SymLab v2 I was able to produce a tetrahedral mesh and solve using OpenFOAM, see attached picture.

Good job! There are some silver faces and gaps in the STEP file which I tried my best to solve, but the result is disgusting..... any suggestions?

gocarts August 30, 2009 11:03

Surface Mesh Quality
 
I guess you know that the quality of the tetrahedral volume elements is heavily dependent on the surface triangle elements.

So my first suggestion is to ensure the faces of the your volume are shaped to avoid poor quality triangles (avoid sharp corners and small areas) - try the 'merge faces' tool to join slivers and the like with adjacent larger faces. Also check for small edges and use the 'merge edges' tool to join them with larger neighbours.

Next try applying size functions (especially curvature) to all your faces, which should carry over surface element sizing into the volume elements, thus avoiding abrupt volume variations.

My Gambit knowledge is a little rusty, so I hope this helps.

PSYMN August 31, 2009 12:41

Got ANSYS Meshing?
 
Since we are already looking at other tools ;),

Note that ANSYS Meshing also has tools such as virtual topology and sizing functions that can also take care of these sorts of problems… These repairs don't cause any geometry issues as you sometimes got with Gambit virtual repairs. This ANSYS Meshing tool is the official migration path for Gambit and relies on a powerful combination of ICEM CFD, TGrid and CFX meshing technology. Its sizing function was originally intended for the next generation of Gambit. ANSYS meshing is included with ANSYS Fluent just as Gambit was included with previous versions of Fluent.


DesignModeler is the ANSYS Geometry repair tool and can handle the more geometry centric repairs (closing holes, Boolean extractions, etc.) and geometry creation. It also features power CAD interfaces that help get your geometry in cleaner so you don't have as much work to do.



Definitely try them out.

PSYMN August 31, 2009 12:44

Don't forget ICEM CFD...
 
ANSYS ICEM CFD is another ANSYS meshing product that is very popular with Fluent users for its ability to walk over slivers and gaps with its patch independent meshing technology.

Fluent users can access this “Extended Meshing” technology as a low cost add-on or thru the CAD2Mesh bundle.

If you are an academic customer, you may find that it is already included in your bundle.


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