## Simulation of electric field inside tube with cutout

Numerical methods and mathematical models of Elmer
alex.neal
Posts: 3
Joined: 24 Mar 2017, 14:31
Antispam: Yes

### Simulation of electric field inside tube with cutout

Hello everyone,

I start the user Elmer and I need a help.

How correctly to set a similar configuration for calculating the electric field inside the tube (black-dielectric):
geo.jpg
The black side - dielectric, orange side - anode&cathode.

I need to calculation electric field inside a tube but with some specificity. So, from 0 to Alpha_1 we calculation with potential Phi1 and Phi2 on r1 distance , but from Alpha_1 to Alpha_2 we calculation with potential Phi1 and Phi3 on r2 distance. How do I set this range in Elmer ? I created geometry in GMesh, namely one cylinder placed in another.

I'll be very grateful for the help!

Regards,
Alex.
Last edited by alex.neal on 18 Sep 2017, 17:27, edited 3 times in total.

mzenker
Posts: 1727
Joined: 07 Dec 2009, 11:49
Location: Germany

### Re: Simulation of electric field inside tube with cutout

Hi,

I cannot open your google drive files, my company's IT blocks them. You can upload the files directly if they are less than 1 MB.
So without knowing the exact geometry, I would propose you open the mesh with ElmerGUI, use the Electrostatic or Static Current solver (depending on the materials: if you have only isolators, it's Electrostatics), set the potential as boundary condition, and that should be it. Then you get the potential as result. To get the field, you can either use the FluxSolver or do it in the postprocessing stage, see this thread: viewtopic.php?f=3&t=4356.

For more information, you can search this forum and consult the documentation: ElmerGUI manual, Solver manual, Models manual, Tutorials.

HTH,
Matthias

alex.neal
Posts: 3
Joined: 24 Mar 2017, 14:31
Antispam: Yes

### Re: Simulation of electric field inside tube with cutout

mzenker wrote:Hi,

I cannot open your google drive files, my company's IT blocks them. You can upload the files directly if they are less than 1 MB.
So without knowing the exact geometry, I would propose you open the mesh with ElmerGUI, use the Electrostatic or Static Current solver (depending on the materials: if you have only isolators, it's Electrostatics), set the potential as boundary condition, and that should be it. Then you get the potential as result. To get the field, you can either use the FluxSolver or do it in the postprocessing stage, see this thread: viewtopic.php?f=3&t=4356.

For more information, you can search this forum and consult the documentation: ElmerGUI manual, Solver manual, Models manual, Tutorials.

HTH,
Matthias
Sorry,

I attached a geometry and thanks for the answer.

Regards,
Alex.

annier
Posts: 1088
Joined: 27 Aug 2013, 13:51
Antispam: Yes

### Re: Simulation of electric field inside tube with cutout

Alex,
1. You need to draw spherical geometries (multibodies) in accordance to your physics.

2. Please see tutorials on capacitances of Elmer (GUI and nonGUI) so that you can basically utilize the PDE of Electrostatics to simulate your geometrical conditions.

Yours Sincerely,
Anil Kunwar

alex.neal
Posts: 3
Joined: 24 Mar 2017, 14:31
Antispam: Yes

### Re: Simulation of electric field inside tube with cutout

annier wrote:Alex,
1. You need to draw spherical geometries (multibodies) in accordance to your physics.

2. Please see tutorials on capacitances of Elmer (GUI and nonGUI) so that you can basically utilize the PDE of Electrostatics to simulate your geometrical conditions.

Yours Sincerely,
Anil Kunwar

Hi, Anil

For first step
I created this geometry:
tube.geo
&
first step.jpg (146.66 KiB) Viewed 453 times
And following the example Electrostatic equation – Capacitance of two ball (p.23) : http://www.nic.funet.fi/index/elmer/doc ... orials.pdf Set the same conditions, except the value for the potentials

Code: Select all

``````Header
CHECK KEYWORDS Warn
Mesh DB "." "."
Include Path ""
Results Directory ""
End

Simulation
Max Output Level = 5
Coordinate System = Cartesian
Coordinate Mapping(3) = 1 2 3
Steady State Max Iterations = 1
Output Intervals = 1
Timestepping Method = BDF
BDF Order = 1
Solver Input File = case.sif
Post File = case.vtu
End

Constants
Gravity(4) = 0 -1 0 9.82
Stefan Boltzmann = 5.67e-08
Permittivity of Vacuum = 1
Boltzmann Constant = 1.3807e-23
Unit Charge = 1.602e-19
End

Body 1
Target Bodies(1) = 3
Name = "Body 1"
Equation = 1
Material = 1
End

Solver 1
Equation = Electrostatics
Variable = Potential
Procedure = "StatElecSolve" "StatElecSolver"
Calculate Electric Field = True
Exec Solver = Always
Stabilize = True
Bubbles = False
Lumped Mass Matrix = False
Optimize Bandwidth = True
Steady State Convergence Tolerance = 1.0e-5
Nonlinear System Convergence Tolerance = 1.0e-7
Nonlinear System Max Iterations = 20
Nonlinear System Newton After Iterations = 3
Nonlinear System Newton After Tolerance = 1.0e-3
Nonlinear System Relaxation Factor = 1
Linear System Solver = Iterative
Linear System Iterative Method = BiCGStab
Linear System Max Iterations = 500
Linear System Convergence Tolerance = 1.0e-10
BiCGstabl polynomial degree = 2
Linear System Preconditioning = Diagonal
Linear System ILUT Tolerance = 1.0e-3
Linear System Abort Not Converged = False
Linear System Residual Output = 1
Linear System Precondition Recompute = 1
End

Equation 1
Name = "Equation 1"
Active Solvers(1) = 1
End

Material 1
Name = "Material 1"
Porosity Model = Always saturated
Relative Permittivity = 1.0
End

Boundary Condition 1
Target Boundaries(1) = 1
Name = "finite"
Electric Infinity BC = True
End

Boundary Condition 2
Target Boundaries(1) = 3
Name = "bc1"
Potential = 1000
End

Boundary Condition 3
Target Boundaries(1) = 2
Name = "bc2"
Potential = 0
End``````
But i can't give the electric field map inside tube with ParaView, because ElmerSolve issues a zero.
Could you help me set the boundary conditions for Elmer ?