i have a problem with the WhitneyAVHarmonicSolver. For verification issues i tried to simulate the ohmic losses in a single wire for different frequencies.
For that i applied a positive and a negative potential on the wire surfaces and fix the magnetic flux density so that a didn't have a z-component.
The resulting fields look's like that of an infinite wire, which was my requirement. In principle i can also see that the current density is higher at the wire skin with increasing frequencies, but the value of the total resistance do not match with the analytic and the FEMM solution. I calculate the ohmic losses with R=U^2/P, where P is the eddy current power.
For frequencies below 100Hz (there is no skin effect) the resistance is ok. Mesh refinements have no effect on the result.
What could be the problem?
Thanks Franz
Code: Select all
Header
CHECK KEYWORDS Warn
Mesh DB "." "singleWire"
Include Path ""
Results Directory ""
End
$ f = 1.e4
$ omega = 2*pi*f
Simulation
Max Output Level = 7
Coordinate System = "Cartesian"
Simulation Type = Steady State
Steady State Max Iterations = 1
! Output Intervals(1) = 0
Solver Input File = singleWire.sif
Post File = singleWire.ep
Coordinate Scaling = Real 0.001
End
Constants
Permittivity of Vacuum = real 8.8542e-12
Permeability of Vacuum = real 1.2566e-6
End
Body 1
Target Bodies(1) = 1
Name = "Body Property 1"
Equation = 1
Material = 2
End
Body 2
Target Bodies(1) = 2
Name = "Body Property 2"
Equation = 1
Material = 1
End
Equation 1
Name = "Equation 1"
Active Solvers(5) = 1 2 3 4 5
End
Solver 1
Equation = Static Current Conduction
Variable = -dofs 1 Potential
Procedure = "StatCurrentSolve" "StatCurrentSolver"
Exec Solver = Always
Calculate Volume Current = True
Calculate Loads = True
Constant Weights = True
Calculate Joule Heating = True
Stabilize = True
Bubbles = False
Lumped Mass Matrix = False
Optimize Bandwidth = True
Steady State Convergence Tolerance = 1.0e-5
Linear System Solver = Iterative
Linear System Iterative Method = BiCGStab
Linear System Max Iterations = 1500
Linear System Convergence Tolerance = 1.0e-12
Linear System Preconditioning = ILU0
Linear System ILUT Tolerance = 1.0e-3
Linear System Abort Not Converged = False
Linear System Residual Output = 10
Linear System Precondition Recompute = 1
End
Solver 2
Equation = "MGDynamics"
Variable = P[P re:1 P im:1]
Procedure = "MagnetoDynamics" "WhitneyAVHarmonicSolver"
Exec Solver = Always
Fix Input Current Density = Logical False
Angular Frequency = $ omega
Steady State Convergence Tolerance = 1.0e-4
Linear System Symmetric = True
Linear System Solver = Iterative
Linear System Iterative Method = BiCGStabL
BiCGStabL Polynomial Degree = 4
Linear System Max Iterations = 5000
Linear System Convergence Tolerance = 1.0e-8
Linear System Preconditioning = None
Linear System ILUT Tolerance = 1.0e-5
Linear System Abort Not Converged = False
Linear System Residual Output = 10
Linear System Precondition Recompute = 1
End
Solver 3
Equation = "MGDynamicsCalc"
Procedure = "MagnetoDynamics" "MagnetoDynamicsCalcFields"
Exec Solver = After all
Linear System Symmetric = True
Potential Variable = String "P"
Angular Frequency = $ omega
Show Angular Frequency = Logical True
Calculate Magnetic Field Strength = Logical True
Calculate Current Density = Logical True
Calculate Joule Heating = Logical True
Calculate Nodal Fields = Logical True
Calculate Magnetic Field Strength = Logical True
Calculate Electric Field = Logical True
Calculate Magnetic Field = Logical True
Steady State Convergence Tolerance = 0
Linear System Symmetric = True
Linear System Solver = "Iterative"
Linear System Preconditioning = None
Linear System Residual Output = 0
Linear System Max Iterations = 500
Linear System Iterative Method = CG
Steady State Convergence Tolerance = 1e-6
Linear System Convergence Tolerance = 1.0e-8
End
Solver 4
Exec Solver = after all
Equation = "ResultOutput"
Procedure = "ResultOutputSolve" "ResultOutputSolver"
Output File Name = singleWire
Vtu format = Logical True
End
Solver 5
Exec Solver = After all
Equation = SaveScalars
Procedure = "SaveData" "SaveScalars"
Filename = "singleWire.dat"
operator 1 = boundary sum
variable 1 = Potential Loads
operator 2 = Volume !convective flux
variable 2 = Joule Heating !Current Density
End
Material 1
Name = "Air"
Relative Permittivity = Real 1
Relative Permeability = Real 1
Electric Conductivity = Real 0
End
Material 2
Name = "Cu"
Relative Permittivity = Real 1
Relative Permeability = Real 1
Electric Conductivity = Real 58e6
End
Boundary Condition 1
Target Boundaries(1) = 1
Name = "PositiveOne"
! Define zero magnetic flux in z-direction
P re {e} 1 = real 0.
P im {e} 1 = real 0.
P re {e} 2 = real 0.
P im {e} 2 = real 0.
! End define zero magnetic flux in z-direction
P re = real 0.001
P im = real 0.
Potential = 0.001
Save Scalars = Logical True
End
Boundary Condition 2
Target Boundaries(1) = 2
Name = "NegativeOne"
! Define zero magnetic flux in z-direction
P re {e} 1 = real 0.
P im {e} 1 = real 0.
P re {e} 2 = real 0.
P im {e} 2 = real 0.
! End define zero magnetic flux in z-direction
P re = real -0.001
P im = real 0.
Potential = -0.001
Save Scalars = Logical True
End
Boundary Condition 3
Target Boundaries(2) = 3 4
Name = "BoundingBoxWire"
! Define zero magnetic flux in z-direction
P re {e} 1 = real 0.
P im {e} 1 = real 0.
P re {e} 2 = real 0.
P im {e} 2 = real 0.
End
Boundary Condition 4
Target Boundaries(1) = 5
Name = "BoundingBox"
P re {e} = real 0.
P im {e} = real 0.
End