WhitneyAVSolver – No Values for Variable AV

Numerical methods and mathematical models of Elmer
anton1ret
Posts: 3
Joined: 08 Aug 2019, 21:12
Antispam: Yes

WhitneyAVSolver – No Values for Variable AV

Task: Magnetic field 3D of two Permanent Magnet

Hello erveryone,

I first tried to calculate a geometry, which I solved successfully two-dimensionally, 3-dimensionally for comparison, before it gets more complicated.

I have tried a lot of settings, including completely different settings of solvers, which I found here in an example. But for the magnetic field AV I only get values close to 0.

The other values are comparable to the two-dimensional solution. Certainly the values are not the same, it is also another idealization and net geometry.

But can anyone tell me how i can get values for the paramter AV.

I attach the input and output file.

Very best regards,
Anton.

Version: 4.5.0 - Build 24.20.100.6292 on Windows 10 and
3.1 Mesa 18.2.8 on Linux 18.04, 64bit
Intel I7-8750H with 32 GB RAM an a fast SSD harddisk

Code: Select all

!!! case.sif !!!
CHECK KEYWORDS Warn
Mesh DB "." "."
Include Path ""
Results Directory ""
End

Simulation
Max Output Level = 5
Coordinate System = Cartesian
Coordinate Scaling = Real 0.001		! mm to meter
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 = case.sif
End

Constants
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 = 2
End

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

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

Solver 1
Equation = MgDyn
Procedure = "MagnetoDynamics" "WhitneyAVSolver"
Variable =  AV
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 = BiCGStab
Linear System Max Iterations = 1000
Linear System Convergence Tolerance = 1.0e-10
BiCGstabl polynomial degree = 2
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 = MgDynPost
Procedure = "MagnetoDynamics" "MagnetoDynamicsCalcFields"
Potential Variable = String "AV"
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 = BiCGStab
Linear System Max Iterations = 1000
Linear System Convergence Tolerance = 1.0e-10
BiCGstabl polynomial degree = 2
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
Calculate Magnetic Vector Potential = logical True
Calculate Magnetic Field Strength = logical True
Calculate Nodal Forces = logical true
End

!!! Save the fields to a file
Solver 3
Exec Solver = After Timestep
Equation = ResultOutput
Procedure = "ResultOutputSolve" "ResultOutputSolver"

Output File Name = "step"
Output Directory = "results"

! VTU format for ParaView with faces' IDs
Save Geometry Ids = logical True
Vtu Format = logical True
!Ascii Output = False
!Binary Output = logical True
!Single Precision = logical True
End

Solver 4
Exec Solver = After Timestep
Equation = SaveScalars
Procedure = "SaveData" "SaveScalars"

Filename = "results.dat"
Output Directory = "results"

Save Component Results = logical True
End

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

Material 1
Name = "air"
Relative Permeability = 1
End

Material 2
Name = "magnet1"
Relative Permeability = 1.216
Magnetization 2 = Real 942.0e3
End

Material 3
Name = "magnet3"
Relative Permeability = 1.216
Magnetization 2 = Real 666.0e3
Magnetization 1 = Real 666.0e3
End

Boundary Condition 1
Target Boundaries(1) = 4
Name = "farvield"
!  Infinity BC = True
AV {e} = Real 0
!  AV {e} 1 = Real 0
!  AV {e} 2 = Real 0
End

Component 1
Name = string "force"
Master Bodies(1) = integer 2
Calculate Magnetic Force = Logical True
!  Save Scalars = Logical True
End

Code: Select all

!!! case.out !!!
ELMER SOLVER (v 8.3) STARTED AT: 2019/08/23 12:19:25
ParCommInit:  Initialize #PEs:            1
MAIN:
MAIN: =============================================================
MAIN: ElmerSolver finite element software, Welcome!
MAIN: This program is free software licensed under (L)GPL
MAIN: Copyright 1st April 1995 - , CSC - IT Center for Science Ltd.
MAIN: Webpage http://www.csc.fi/elmer, Email elmeradm@csc.fi
MAIN: Version: 8.3 (Rev: 432ee0dd, Compiled: 2018-12-18)
MAIN:  Running one task without MPI parallelization.
MAIN:  Running with just one thread per task.
MAIN:  Lua interpreted linked in.
MAIN: =============================================================
MAIN:
MAIN:
MAIN: -------------------------------------
MAIN: Reading Model: case.sif
LoadInputFile: Scanning input file: case.sif

LoadMesh: Base mesh name: ./.

LoadMesh: Scaling coordinates: 1.000E-03 1.000E-03 1.000E-03

LoadMesh: Elapsed REAL time:     2.2330 (s)

MAIN: -------------------------------------
OptimizeBandwidth: ---------------------------------------------------------

OptimizeBandwidth: Computing matrix structure for: mgdyn...done.
OptimizeBandwidth: Half bandwidth without optimization: 269367
OptimizeBandwidth:

OptimizeBandwidth: Bandwidth Optimization ...done.
OptimizeBandwidth: Half bandwidth after optimization: 13810
OptimizeBandwidth: ---------------------------------------------------------

OptimizeBandwidth: ---------------------------------------------------------
OptimizeBandwidth: Computing matrix structure for: mgdynpost...done.
OptimizeBandwidth: Half bandwidth without optimization: 40470
OptimizeBandwidth:

OptimizeBandwidth: Bandwidth Optimization ...done.
OptimizeBandwidth: Half bandwidth after optimization: 3303
OptimizeBandwidth: ---------------------------------------------------------

MAIN:
MAIN: -------------------------------------
MAIN:  Steady state iteration:            1
MAIN: -------------------------------------
MAIN:
SingleSolver: Attempting to call solver
SingleSolver: Solver Equation string is: mgdyn
WhitneyAVSolver: Solving the AV equations with edge elements

MGDynAssembly: Elapsed REAL time:     3.2430 (s)
DefUtils::DefaultDirichletBCs: Setting Dirichlet boundary conditions

DefUtils::DefaultDirichletBCs: Dirichlet boundary conditions set

CRS_IncompleteLU: ILU(0) (Real), Starting Factorization:

CRS_IncompleteLU: ILU(0) (Real), NOF nonzeros:   4302723
CRS_IncompleteLU: ILU(0) (Real), filling (%) :       100
CRS_IncompleteLU: ILU(0) (Real), Factorization ready at (s):     0.11

10 0.4725E-01

20 0.3139E-02

30 0.5314E-03

40 0.5719E-04

50 0.2009E-05

60 0.4904E-06

70 0.4335E-07

80 0.1749E-08

90 0.2213E-09

98 0.9926E-10
ComputeChange: NS (ITER=1) (NRM,RELC): ( 0.27985351E-05  2.0000000     ) :: mgdyn

MGDynAssembly: Elapsed REAL time:     3.2150 (s)
DefUtils::DefaultDirichletBCs: Setting Dirichlet boundary conditions

DefUtils::DefaultDirichletBCs: Dirichlet boundary conditions set
CRS_IncompleteLU: ILU(0) (Real), Starting Factorization:

CRS_IncompleteLU: ILU(0) (Real), NOF nonzeros:   4302723
CRS_IncompleteLU: ILU(0) (Real), filling (%) :       100
CRS_IncompleteLU: ILU(0) (Real), Factorization ready at (s):     0.09
1 0.7576E-10
ComputeChange: NS (ITER=2) (NRM,RELC): ( 0.27985351E-05 0.11223008E-11 ) :: mgdyn
ComputeChange: SS (ITER=1) (NRM,RELC): ( 0.27985351E-05  2.0000000     ) :: mgdyn

SingleSolver: Attempting to call solver
SingleSolver: Solver Equation string is: mgdynpost
MagnetoDynamicsCalcFields: Computing postprocessed fields
WARNING:: GetPermittivity: Permittivity not defined in material, defaulting to that of vacuum

CRS_IncompleteLU: ILU(0) (Real), Starting Factorization:

CRS_IncompleteLU: ILU(0) (Real), NOF nonzeros:    582129
CRS_IncompleteLU: ILU(0) (Real), filling (%) :       100
CRS_IncompleteLU: ILU(0) (Real), Factorization ready at (s):     0.02
5 0.3783E-11
ComputeChange: NS (ITER=1) (NRM,RELC): ( 0.10064024      2.0000000     ) :: mgdynpost
5 0.4138E-11
ComputeChange: NS (ITER=2) (NRM,RELC): ( 0.28682764     0.96104684     ) :: mgdynpost
5 0.2846E-11
ComputeChange: NS (ITER=3) (NRM,RELC): ( 0.62167789E-01  1.2874659     ) :: mgdynpost

5 0.3727E-11
ComputeChange: NS (ITER=4) (NRM,RELC): (  73921.307      1.9999966     ) :: mgdynpost
5 0.3896E-11
ComputeChange: NS (ITER=5) (NRM,RELC): (  193490.62     0.89427059     ) :: mgdynpost
5 0.2792E-11
ComputeChange: NS (ITER=6) (NRM,RELC): (  46163.342      1.2295000     ) :: mgdynpost
5 0.3674E-11
ComputeChange: NS (ITER=7) (NRM,RELC): ( 0.98640331E-03  1.9999999     ) :: mgdynpost

5 0.4255E-11
ComputeChange: NS (ITER=8) (NRM,RELC): ( 0.29531633E-03  1.0783746     ) :: mgdynpost
5 0.3727E-11
ComputeChange: NS (ITER=9) (NRM,RELC): ( 0.16007241E-02  1.3769831     ) :: mgdynpost
MagnetoDynamicsCalcFields:  Eddy current power:    0.0000000000000000
MagnetoDynamicsCalcFields:  (Electro)Magnetic Field Energy:    7.1543214362065717
ComputeChange: SS (ITER=1) (NRM,RELC): ( 0.16007241E-02  2.0000000     ) :: mgdynpost
SingleSolver: Attempting to call solver
SingleSolver: Solver Equation string is: resultoutput
ResultOutputSolver: -------------------------------------
ResultOutputSolve: Saving with prefix: step
ResultOutputSolver: Creating list for saving - if not present
CreateListForSaving: Field Variables for Saving
ResultOutputSolver: Saving in unstructured VTK XML (.vtu) format
VtuOutputSolver: Saving results in VTK XML format with prefix: step
VtuOutputSolver: Saving number of partitions: 1
WriteVtuFile: Writing variable: magnetic flux density e
WriteVtuFile: Writing variable: magnetic vector potential e
WriteVtuFile: Writing variable: magnetic field strength e
WriteVtuFile: Writing variable: nodal force e

ResultOutputSolver: -------------------------------------
SingleSolver: Attempting to call solver
SingleSolver: Solver Equation string is: savescalars
SaveScalars: -----------------------------------------
SaveScalars: Saving scalar values of various kinds
SaveScalars: Saving names of values to file: results/results.dat.names
SaveScalars: Saving values to file: results/results.dat
ElmerSolver: *** Elmer Solver: ALL DONE ***

ElmerSolver: The end
SOLVER TOTAL TIME(CPU,REAL):        20.47       20.47
ELMER SOLVER FINISHED AT: 2019/08/23 12:19:46

mzenker
Posts: 1955
Joined: 07 Dec 2009, 11:49
Location: Germany

Re: WhitneyAVSolver – No Values for Variable AV

Hi,

in your output, there is a warning:

Code: Select all

WARNING:: GetPermittivity: Permittivity not defined in material, defaulting to that of vacuum
Could this be the cause of your problem?

HTH,
Matthias

anton1ret
Posts: 3
Joined: 08 Aug 2019, 21:12
Antispam: Yes

Re: WhitneyAVSolver – No Values for Variable AV

Hi Mathias,

thank you for your reply. I have now tested it with indication of permittivity with the same problem. It also works without specification in the two-dimensional calculation with the same warning.

Cheers, Anton.

mzenker
Posts: 1955
Joined: 07 Dec 2009, 11:49
Location: Germany

Re: WhitneyAVSolver – No Values for Variable AV

Hi,

I don't have any experience with magnetic simulation myself, so I cannot help much further.
Just a thought: Are you sure that the geometries are comparable? In 2D simulations Elmer normally assumes 1 m thickness for the 3rd dimension, so your 3D geometry should take that into account.
For the rest, someone with knowledge about the magnetic solvers has to take over...

Matthias

anton1ret
Posts: 3
Joined: 08 Aug 2019, 21:12
Antispam: Yes

Re: WhitneyAVSolver – No Values for Variable AV

Hi Matthias,

thank you for trying to help me.

I have three-dimensional a thickness of 50mm and multiply the relevant results by 20.
For sure the values are not the same but nearby. It is also another idealization and net geometry.

Cheers, Anton.