Concentration Distribution in Cone Geometry

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VVS
Posts: 23
Joined: 30 Aug 2013, 17:43
Antispam: Yes

Concentration Distribution in Cone Geometry

Post by VVS »

Hi Everyone!

I want to simulate the Concentration Distribution in a cone geometry. To do this I can use the Heat Equation which is the same as for mass transport.
I have a doubt which I want to clear:

I am using Gmsh to create the mesh. The cone mesh will have an edge with a certain thickness, which is made out of glass. The interior of the cone is made out of water. How do I make sure that I get different bodies for the cone geometry?

thank you
VVS
mzenker
Posts: 1999
Joined: 07 Dec 2009, 11:49
Location: Germany

Re: Concentration Distribution in Cone Geometry

Post by mzenker »

Hi,

just define two bodies in gmsh....

HTH,

Matthias
VVS
Posts: 23
Joined: 30 Aug 2013, 17:43
Antispam: Yes

Re: Concentration Distribution in Cone Geometry

Post by VVS »

Hi,

Thanks. But I only know how to define Physical Volumes or Surfaces. How do I define bodies in gmsh?

thanks
VVS
mzenker
Posts: 1999
Joined: 07 Dec 2009, 11:49
Location: Germany

Re: Concentration Distribution in Cone Geometry

Post by mzenker »

Hi,

you don't need to define anything as physical. Just make sure that you have the volumes and surfaces you need in gmsh, mesh, and save as .msh with "save all (ignore physical groups)" checked.

HTH,

Matthias
VVS
Posts: 23
Joined: 30 Aug 2013, 17:43
Antispam: Yes

Re: Concentration Distribution in Cone Geometry

Post by VVS »

Thanks Matthias!

It works now.

But now I have some more questions:

I want the top surface of the cone to have a uniform and constant concentration distribution. Do I have to use a body force or is it enough if I just specify a boundary condition?

Also I have to specify a boundary condition at the edge of the interior cone. How can I select that boundary if I can't see it in the Mesh?

thanks
VVS
mzenker
Posts: 1999
Joined: 07 Dec 2009, 11:49
Location: Germany

Re: Concentration Distribution in Cone Geometry

Post by mzenker »

Hi,

if I understand correctly, you use temperature as equivalent for concentration. To have a uniform temperature at one surface you need a boundary condition.

It is often not possible to select boundaries in ElmerGUI, especially in 3D. You don't need to do it if you know the boundary number - just check the relevant boundaries in the Model->Boundary Condition dialog. If you don't know the number, you can display all surface numbers in ElmerGUI with View->Numbering->Boundary Index. The GUI becomes very slow then, so zooming into your geometry is not comfortable. Another way is to translate the mesh back into gmsh format (you need to do that since Elmer renumbers everything at import). cd to the directory where your Elmer mesh files are and say

Elmergrid 2 4 mesh

Then there is a file mesh.msh which you can open with gmsh and find out whioch number your boundary has.

HTH,

Matthias
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