electric field with a plate and two sets of wires

Numerical methods and mathematical models of Elmer
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bbeltran
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electric field with a plate and two sets of wires

Post by bbeltran » 08 Nov 2017, 22:10

Hi all,

I am trying to solve the electric field (potential) for the case of a gas detector where we have a plane with a set potential at the bottom and two sets of wires (anodes and cathodes ) 20 cm above the plane, with 0.5 cm pitch and 0.5 cm separation between the layers of wires.
I have created the mesh with Gmsh and I am using ElmerSover. Also I am using Paraview to visualize the result of ElmerSolver. I am attaching my .geo and .sif files.

My meshing and solver commands are:

> gmsh betacage.geo -3 -order 2
> ElmerGrid 14 2 betacage.msh -autoclean
> ElmerSolver betacage.sif


I have a potenital set for the plane a the bottom of 100 V and for the set of wires at the top of 3000V. But somehow when I solve the field the potential is 100V all across my device, so somehow I suspect that ElmerSolver does not see the 3000V potential in the wires, I must have something wrong either on my .geo or my .sif file. Could any of you please have a look at my files and maybe spot what I would need to change so that the potential at the top set of wires is read by ElmerSolver ?

Thanks a lot
Attachments
betacage.geo
(4.45 KiB) Downloaded 110 times
betacage.sif
(1.99 KiB) Downloaded 113 times
Last edited by bbeltran on 08 Nov 2017, 22:11, edited 1 time in total.

bbeltran
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Re: electric field with a plate and two sets of wires

Post by bbeltran » 08 Nov 2017, 22:10

these are the other files needed
Attachments
gf_x_cylinder.geo
(2.66 KiB) Downloaded 109 times
gf_rectangle.geo
(2.93 KiB) Downloaded 104 times
gf_cylinder.geo
(2.63 KiB) Downloaded 106 times

raback
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Re: electric field with a plate and two sets of wires

Post by raback » 09 Nov 2017, 01:41

Hi

First problem: your BCs 2 and 3 refer to the same Target Boundary.

-Peter

bbeltran
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Re: electric field with a plate and two sets of wires

Post by bbeltran » 14 Nov 2017, 21:42

Hi Peter,

Thanks for your feedback !
Ok, So I have set the numbering of Target Boundaries in the .sif file to correspond with the physical surfaces as declares and numbered in the .geo file. Is that how it should be ? ElmerSolver still does not assign voltages to the wires, so I still must have something wrong.

Thanks

For reference here is my edited .sif file

! Botton plane
Boundary Condition 1
Target Boundaries = 1
Potential = 100
End

! Anode wires
Boundary Condition 2
Target Boundaries = 2
Potential = 3000
End

! Cathode wires
Boundary Condition 3
Target Boundaries = 3
Potential = 0
End

mzenker
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Joined: 07 Dec 2009, 11:49
Location: Germany

Re: electric field with a plate and two sets of wires

Post by mzenker » 15 Nov 2017, 12:13

Hi,

since you used the -autoclean option when converting your .msh to elmer format, the numbering of bodies and boundaries has probably changed. Normally ElmerGrid tells you in the output to the terminal which number is assigned to which number in the .msh file. So you might re-run ElmerGrid to see if your numbering in the .sif is correct.

HTH,

Matthias

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