## Problems with coilSolver

Numerical methods and mathematical models of Elmer
lazyTom
Posts: 47
Joined: 05 Jun 2013, 01:32
Antispam: Yes

### Problems with coilSolver

Hi all,

I'm trying to solve for the current in a 3D closed coil (see picture below)
closed_loop_std_10_turns.jpg (63.83 KiB) Viewed 1792 times

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.
closed_loop_std_10_turns_current.jpg (13.07 KiB) Viewed 1791 times

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)

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
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
raback
Posts: 4143
Joined: 22 Aug 2009, 11:57
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Location: Espoo, Finland
Contact:

### Re: Problems with coilSolver

Hi Marco

Well, the CoilSolver has some heuristics which is meant for simple closed coils. It might be able to pull it of for cocentric loops but certainly spiral with the wire joining the ends a is too difficult. I would rather create a mesh with possibility to set voltages at the ends of the wire. Your mesh is already quite complex, it does not make it much more complex

-Peter
lazyTom
Posts: 47
Joined: 05 Jun 2013, 01:32
Antispam: Yes

### Re: Problems with coilSolver

Hi Peter,

Will do

thanks for clarifying.

Marco