Elmer Discussion Forum

Posted: **02 May 2016, 18:39**

Hi,

At the moment I try to create some simple cases for myself to get into Elmer electromagnetic simulation. At the moment I have a problem with the boundary condition for an infinite long wire. My model consists of 4 cylinders/hollow cylinders. In the middle the wire, than air, electrical steel (at the moment with const. rel. permeability) and again air as last material (picture).

: hidden surfaces (air) for better overview; model.png (151.23 KiB) Viewed 1923 times

In my understanding the bc in z-driection have to be Magnetic Flux Density 3 = Real 0.
The results with different bc:

1. Magnetic Flux Density 3 = Real 0 at every face in z-direction (also at the two ends of the wire)
-->WhitneyAVSolver ends with:

Program received signal SIGSEGV: Segmentation fault - invalid memory reference.

Backtrace for this error:
#0 ffffffffffffffff

2. Same error for other bc like Magnetic Flux Density 3 = Real 0 at every face in z-direction instead of the faces for the wire. But at first there wasn't this error but the solution of statcurrent or whitneyav doesn't converge. Yet I can't rebiuld this error. Anyone an idea what this error means or how to avoid it? What bc should be set for an infinite long wire?

I usw Elmer under Windows 10 and 7 (Elmer 8.0) with a model created in Salome.

The SIF-file:

Code: Select all

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

Simulation
  Max Output Level = 10
  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 = inf.sif
  Post File = inf.ep
Coordinate Scaling = 1e-3
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) = 10
  Name = "Body 1"
  Equation = 1
  Material = 1
  Body Force = 1
End

Body 2
  Target Bodies(1) = 11
  Name = "Body 2"
  Equation = 2
  Material = 2
End

Body 3
  Target Bodies(1) = 12
  Name = "Body 3"
  Equation = 2
  Material = 3
End

Body 4
  Target Bodies(1) = 13
  Name = "Body 4"
  Equation = 2
  Material = 2
End

Solver 2
  Equation = MgDyn
  Variable = AV
  Fix Input Current Density = True
  Procedure = "MagnetoDynamics" "WhitneyAVSolver"
  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 = CG
  Linear System Max Iterations = 5000
  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

Solver 3
  Equation = MgDynPost
  Calculate Magnetic Field Strength = True
  Potential Variable = AV
  Procedure = "MagnetoDynamics" "MagnetoDynamicsCalcFields"
  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 = CG
  Linear System Max Iterations = 5000
  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

Solver 1
  Equation = Static Current Conduction
  Calculate Volume Current = True
  Variable = Potential
  Procedure = "StatCurrentSolve" "StatCurrentSolver"
  Exec Solver = Before Simulation
  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 = CG
  Linear System Max Iterations = 5000
  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

Solver 4
  Equation = Result Output
  Procedure = "ResultOutputSolve" "ResultOutputSolver"
  Output Format = Vtu
  Output File Name = inf
  Exec Solver = After Timestep
End

Equation 1
  Name = "Wire"
  Active Solvers(4) = 2 3 1 4
End

Equation 2
  Name = "Air+Core"
  Active Solvers(3) = 2 3 4
End

Material 1
  Name = "Copper"
  Electric Conductivity = 59.59e6
  Porosity Model = Always saturated
  Density = 8960.0
  Relative Permeability = 1
End

Material 2
  Name = "Air"
  Electric Conductivity = 0
  Porosity Model = Always saturated
  Density = 1.205
  Relative Permeability = 1
End

Material 3
  Name = "Steel"
  Electric Conductivity = 1.449e6
  Porosity Model = Always saturated
  Density = 8960.0
  Relative Permeability = 1000
End

Body Force 1
  Name = "BodyForce 1"
  Current Density 1 = Equals Volume Current 1
  Current Density 3 = Equals Volume Current 3
  Current Density 2 = Equals Volume Current 2
End

Boundary Condition 1
  Target Boundaries(1) = 5 
  Name = "Ground"
  Potential = 0
  Magnetic Flux Density 3 = Real 0
End

Boundary Condition 2
  Target Boundaries(1) = 6 
  Name = "Potential"
  Current Density = 1e7
  Magnetic Flux Density 3 = Real 0
End

Boundary Condition 3
  Target Boundaries(1) = 4 
  Name = "Border"
  AV {e} = 0
End

Boundary Condition 4
  Target Boundaries(6) = 1 2 3 7 8 9 
  Name = "inf"
  Magnetic Flux Density 3 = Real 0
End

Posted: **03 May 2016, 13:12**

I got it on my own. In fact pretty easy. Only have to set AV {e} 2 = 0 and AV {e} 1 = 0 for all BCs in z-direction

Elmer Discussion Forum

BC for infinite longe wire

BC for infinite longe wire

Re: BC for infinite longe wire