I have a problem with an electromagnetic model. The model describes a single wire surrounded by air and and an iron cylinder (picture). The solution of the magnetic field strength is lower at increasing distance to the wire than it should be (f.e. r=50mm -> H=1450A/m instead of 2500A/m or r=100mm -> H=200A/m instead of 1250A/m).

Anyone an idea what i have done wrong?

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 = sw_fine.sif
Post File = sw_fine.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) = 1
Name = "Body 1"
Equation = 1
Material = 1
Body Force = 1
End
Body 2
Target Bodies(1) = 2
Name = "Body 2"
Equation = 2
Material = 2
End
Body 3
Target Bodies(1) = 3
Name = "Body 3"
Equation = 2
Material = 3
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 = sw_fine
Exec Solver = After Timestep
End
Equation 1
Name = "Wire"
Active Solvers(4) = 2 3 1 4
End
Equation 2
Name = "Core+Air"
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 = "Steel"
Electric Conductivity = 1.449e6
Porosity Model = Always saturated
Density = 7850.0
Relative Permeability = 1000
End
Material 3
Name = "Air"
Electric Conductivity = 0
Porosity Model = Always saturated
Density = 1.205
Relative Permeability = 1
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) = 8
Name = "Ground"
Potential = 0
End
Boundary Condition 2
Target Boundaries(1) = 2
Name = "Current"
Current Density = 1e7
End
Boundary Condition 3
Target Boundaries(3) = 1 7 10
Name = "Border"
AV {e} = 0
End
```