How to simulate electric field around a livewire?

[mzenker]

... but beware: if you edit the sif, your changes will be overwritten with the next project save. So if you want to continue with the GUI for that project, do the changes within the GUI.

Matthias

[annier]

Yes, Matthias is right. You cannot use "Potential" for both solvers. Use, for example, PotantialA and PotentialB instead. Then solve the equations hierarchically, probably the conductor first (PotentialA) and set the BC for the insulator at the boundary as

Code: Select all

PotentialB = Equals PotentialA

Hi,
Nice concept for using a single variable as two variables in two different solvers.


Yours Sincerely,
Anil Kunwar

[annier]

Hi Sprite,
Peter's suggestion of editing sif is for Elmer NonGUI (or ElmerGUI before editing and ElmerNonGUI afterwards) and Matthias' suggestion is for full scaled Elmer GUI.

Yours Sincerely,
Anil Kunwar

[sprite]

Hello all.
I've tried to change the variable name, then Elmer solves nothing...

My sif file:(When I change "variable=PotentialA" to "variable=Potential",it works well. )

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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
  Simulation Type = Steady state
  Steady State Max Iterations = 1
  Output Intervals = 1
  Timestepping Method = BDF
  BDF Order = 1
  Solver Input File = case.sif
  Post File = case.ep
End

Constants
  Gravity(4) = 0 -1 0 9.82
  Stefan Boltzmann = 5.67e-08
  Permittivity of Vacuum = 8.8542e-12
  Boltzmann Constant = 1.3807e-23
  Unit Charge = 1.602e-19
End

Body 1
  Target Bodies(1) = 1
  Name = "Body 1"
  Equation = 2
  Material = 1
End

Body 2
  Target Bodies(1) = 2
  Name = "Body 2"
  Equation = 1
  Material = 2
End

Solver 1
  Equation = Static Current Conduction
  Procedure = "StatCurrentSolve" "StatCurrentSolver"
  Variable = PotentialA
  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

Equation 2
  Name = "Equation 2"
End

Material 1
  Name = "Air (room temperature)"
  Viscosity = 1.983e-5
  Heat expansion Coefficient = 3.43e-3
  Heat Conductivity = 0.0257
  Relative Permittivity = 1.00059
  Sound speed = 343.0
  Heat Capacity = 1005.0
  Density = 1.205
End

Material 2
  Name = "Copper (generic)"
  Heat expansion Coefficient = 16.5e-6
  Electric Conductivity = 59.59e6
  Electric Conductivity = 59.59e6
  Heat Conductivity = 401.0
  Sound speed = 3810.0
  Heat Capacity = 385.0
  Mesh Poisson ratio = 0.34
  Density = 8960.0
  Poisson ratio = 0.34
  Youngs modulus = 115.0e9
End

Boundary Condition 1
  Target Boundaries(1) = 8 
  Name = "BoundaryCondition 1"
  Potential = 5
End

Boundary Condition 2
  Target Boundaries(1) = 9 
  Name = "BoundaryCondition 2"
  Potential = 0
End

then the log

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ELMER SOLVER (v 8.0) STARTED AT: 2015/11/16 19:17:41
ParCommInit:  Initialize #PEs:            1
MAIN: 
MAIN: =============================================================
MAIN: ElmerSolver finite element software, Welcome!
MAIN: This program is free software licensed under (L)GPL
MAIN: Copyright 1st April 1995 - , CSC - IT Center for Science Ltd.
MAIN: Webpage http://www.csc.fi/elmer, Email elmeradm@csc.fi
MAIN: Version: 8.0 (Rev: Release, Compiled: 2015-05-04)
MAIN: =============================================================
MAIN: 
MAIN: 
MAIN: -------------------------------------
MAIN: Reading Model: case.sif

Loading user function library: [StatCurrentSolve]...[StatCurrentSolver_Init0]
LoadMesh: Base mesh name: ./.

LoadMesh: Elapsed time (CPU,REAL):     0.6140    0.6140 (s)

MAIN: -------------------------------------
Loading user function library: [StatCurrentSolve]...[StatCurrentSolver_Init]
Loading user function library: [StatCurrentSolve]...[StatCurrentSolver]
OptimizeBandwidth: ---------------------------------------------------------
OptimizeBandwidth: Computing matrix structure for: static current conduction...done.
OptimizeBandwidth: Half bandwidth without optimization: 2550
OptimizeBandwidth: 
OptimizeBandwidth: Bandwidth Optimization ...done.
OptimizeBandwidth: Half bandwidth after optimization: 58
OptimizeBandwidth: ---------------------------------------------------------
MAIN: 
MAIN: -------------------------------------
MAIN:  Steady state iteration:            1
MAIN: -------------------------------------
MAIN: 

SingleSolver: Attempting to call solver
SingleSolver: Solver Equation string is: static current conduction
StatCurrentSolve: -------------------------------------
StatCurrentSolve: STAT CURRENT SOLVER:
StatCurrentSolve: -------------------------------------
StatCurrentSolve: Static current iteration: 1

DefUtils::DefaultDirichletBCs: Setting Dirichlet boundary conditions
DefUtils::DefaultDirichletBCs: Dirichlet boundary conditions set
StatCurrentSolve:  Assembly (s)          :  0.21499999999999986
SolveSystem: Solution trivially zero!
StatCurrentSolve:  Solve (s)             :   0.0000000000000000
ComputeChange: SS (ITER=1) (NRM,RELC): (  0.0000000      0.0000000     ) :: static current conduction
WritePostFile: Saving results in ElmerPost format to file ./case.ep

In the ElmerVTK, PotentialA shows nothing.
What's wrong with it?

[raback]

Hi, You should also give the Dircihlet BC for the newly named variable. -Peter

[sprite]

Hello Peter.
I found that.
I should use "PotentialA = Real 5" instead.
Thank you very much.

[Wil]

Hallo sprite,
I had a similar problem and could solve most of it using some hints form this post.
Are you able to calculate the electric field inside the air?
Please have a look at a simple model I placed in one of my posts where I could solve the potential in a "Air"-domain next to a "Copper"-domain but I could not solve the Electric field and energy.
viewtopic.php?f=7&t=4085&p=14479&sid=29 ... a1b#p14479

You maybe have the same problem (no field and energy) or you have a hint for me what is wrong.

BR,
Wil