I'm trying to solve for the current in a 3D closed coil (see picture below)

Unfortunately the solution that I obtain with coil solver is not plausible (see picture below, a volumetric view of current density magnitude) because in this case current is a solenoidal field.

Can anybody help me out with this problem?

Here is the link to mesh and sif file: https://www.dropbox.com/s/rpc51jatffecd ... l.zip?dl=0

The sif file can be found also below

Code: Select all

```
!!------ Skeleton for body section -----
!Body 1 = coil
!Body 2 = air top
!Body 3 = air bot
!BC 01 = external air (where vector potential is assumed to be 0)
Header
Check Keywords "Warn"
Mesh DB "." "closed_loop_std_10_turns"
Include Path ""
Results Directory ""
End
Simulation
Coordinate System = Cartesian
Coordinate Mapping(3) = 1 2 3
! Coordinate Scaling=0.001
Simulation Type = Steady
Steady State Max Iterations = 1
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(2) = 2 3
Name = "Air"
Equation = 2
Material = 1
End
Body 2
Target Bodies(1) = 1
Name = "3D Coil 1"
Equation = 1
Material = 2
Body Force = 1
End
Material 1
Name = "Air (room temperature)"
Viscosity = 1.983e-5
Heat expansion Coefficient = 3.43e-3
Heat Conductivity = 0.0257
Sound speed = 343.0
Density = 1.205
Heat Capacity = 1005.0
Relative Permittivity = Real 1
Relative Permeability = Real 1
Electric Conductivity = Real 0
End
Material 2
Name = "Copper (generic)"
Heat expansion Coefficient = 16.5e-6
Heat Conductivity = 401.0
Sound speed = 3810.0
Heat Capacity = 385.0
Density = 8960.0
Mesh Poisson ratio = 0.34
Poisson ratio = 0.34
Youngs modulus = 115.0e9
Relative Permittivity = Real 1
Relative Permeability = Real 1
Electric Conductivity = Real 5.96e7
End
Equation 1
Name = "Equation A"
Active Solvers(3) = 1 2 3
End
Equation 2
Name = "Equation magnetic field"
Active Solvers(2) = 2 3
End
Solver 1
Equation = "CoilSolver"
Procedure = "CoilSolver" "CoilSolver"
! Linear System Solver = direct
Linear System Solver = "Iterative"
Linear System Preconditioning = ilu2
Linear System Max Iterations = 1000
Linear System Convergence Tolerance = 1e-10
! Linear System Iterative Method = BiCGStabL
! BicGStabL Polynomial Degree = 4
Linear System Residual Output = 20
! Steady State Convergence Tolerance = 1e-06
Desired Coil Current = Real 1
Calculate Coil Current = Logical True
Optimize Bandwidth = False
Nonlinear System Consistent Norm = Logical True
Coil Closed = Logical True
End
!===============================================
!=========== MAGNETIC FIELD SOLVER =============
Solver 2
! Exec Solver = Never
Equation = "MGDynamics"
Variable = P
Procedure = "MagnetoDynamics" "WhitneyAVSolver"
Fix Input Current Density = Logical True
! Linear System Symmetric = True
! Optimize Bandwidth = True
Steady State Convergence Tolerance = 1e-09
Nonlinear System Convergence Tolerance = 1.0e-8
Nonlinear System Max Iterations = 1
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 = TFQMR
! Linear System Iterative Method = GC
! Linear System Iterative Method = GCR
! Linear System Iterative Method = BiCGStab
! Linear System Iterative Method = BiCGStab2
! Linear System Iterative Method = BiCGStabl
! BicGStabL Polynomial Degree = 4
! Linear System Preconditioning = none
! Linear System Preconditioning = ILU2
! Linear System ILUT Tolerance = 1.0e-3
! Linear System Precondition Recompute = 1
! Linear System Residual Output = 20
! Linear System Residual Output = 1
Linear System Max Iterations = 1400 !5000
Linear System Convergence Tolerance = 1.0e-8
Linear System Abort Not Converged = False
! Edge Basis = Logical True
! Apply Mortar BCs = Logical True
! Mortar BCs additive = True
End
Solver 3
! Exec Solver = Never
Equation = "MGDynamicsCalc"
Procedure = "MagnetoDynamics" "MagnetoDynamicsCalcFields"
Potential Variable = P
Calculate Current Density = Logical True
Calculate Electric Field = Logical True
Calculate Magnetic Field Strength = Logical True
Calculate Magnetic Field Density = Logical True
Steady State Convergence Tolerance = 1e-09
Linear System Solver = "Iterative"
! Linear System Iterative Method = CG
Linear System Iterative Method = BiCGStab
Linear System Max Iterations = 5000
Linear System Convergence Tolerance = 1.0e-8
End
Solver 4
! Equation = Result Output
! Exec Solver = Never
Procedure = "ResultOutputSolve" "ResultOutputSolver"
Binary Output = True
Output Format = vtu
Output File Name = results
End
Solver 5
! Equation = "scalars"
! Exec Solver = Never
procedure = "SaveData" "SaveScalars"
Filename = "data_scalars.dat"
End
Boundary Condition 1
Target Boundaries(1) = 1
Name = "Outer space"
P {e}= real 0
End
Body Force 1
Name = "Current Density"
! Current Density 1 = Equals Volume current 1
! Current Density 2 = Equals Volume current 2
! Current Density 3 = Equals Volume current 3
Current Density 1 = Equals CoilCurrent 1
Current Density 2 = Equals CoilCurrent 2
Current Density 3 = Equals CoilCurrent 3
End
```

Many thanks,

Marco