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Tom July 19, 2002 05:53

Trouble in Gambit

I have a trouble in makeing a mesh of Fluent. My model is a 3d bifurcate pipe which diameter is changed along the pipe. I hope to mesh the model to hexahedron mesh, but all ways I known were invalidated. However I believe the model should be meshed to hexahedron mesh because I had read the same model and its mesh in a paper.

Is someone give me a better and successful way ?

Thanks in advance

Christian July 19, 2002 09:34

Re: Trouble in Gambit
You don't give many informations about the specific problems, but try dividing the volume into smaller volumes. It might be easier to mesh the total volume. And try to find an appropriate place to start the meshing and the proceed onwards.

Good luck, Christian

Puck July 19, 2002 09:46

Re: Trouble in Gambit
Regarding meshing in gambit, Is it allrite to ignore warning messages when meshing a volume? And also, Which meshing scheme is the best to use when meshing circular ducts?

Laika July 19, 2002 10:14

Re: Trouble in Gambit
What kind of warnings.

For a duct: put a boundary-layer-mesh at the walls, mesh an end face with quad pave and mesh the volume with the cooper scheme.

Laika, still orbiting

Puck July 19, 2002 10:44

Re: Trouble in Gambit
hi, thnx for replying...I have to attach a boundary layer before i can mesh?..havent been doing that all the while. tell you my problem..I ahve to model a hair dryer but doing a schematic version of it.. I have to put an annulus of a small duct inside that of a bigger duct. The bigger duct is a united volume consisting of a frustrum and a cylinder. Untilnow, i hve been meshing using hex/wedge without using boundary layer..somtimes i get the message that copper scheme cant support the meshing etc.. Worried that these mite afftec my iterated results.. Plz help..

Laika July 22, 2002 03:36

Re: Trouble in Gambit
Of course you can mesh without a boundary layer mesh, but to obtain good results, it's good practice to use a boundary layer-mesh at the walls of ducts.

Try to use the cooper scheme. It's by far the best scheme to mesh ducts. Or try at least to mesh most of your duct with the cooper scheme. Decompose your volume for it!


Laika, still orbiting

Soma July 22, 2002 17:48

Re: Trouble in Gambit
I think Cooper scheme will not work with such kind of geometry unless one decompose the volume. If your want to mesh as single volume try TGRID scheme

Laika July 23, 2002 03:26

Re: Trouble in Gambit
If your duct geometry is not extremely complicated, you should decompose and hex-mesh the most of your geometry. Tet-meshing will blow up the simulation-time. If you can hex-mesh, hex-mesh!

greetings, Laika, still orbiting

Puck July 23, 2002 09:17

Re: Trouble in Gambit
Thnx for all your replies..You people proof to be more helpful than my professors:P anyways, what is the technique to apply boudary layer meshing? Cos when i apply boundary layer, my meshing got error. Whta would be the best way to mesh a duct of radius 4 and length 10cm? Plz reply...

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