i continue to testing FreeCAD FEM with ELmer.
I had trying Electrostatic equation – Capacitance of perforated plate calculation.
In ElmerGUI i retrieved the capacitance result of ~216 fF (2.1636998485501316E-013)
but in FreeCAD FEM tutorial for this identical use case i obtain : 2.1650117323981551E-010
Perhaps is it a problem of unity ? What is the best choice for the unity system in freecad ?
If this choice has no impact, what is the possible problem ?
ElmerGUI (standalone) output :
Code: Select all
StatElecSolver: -------------------------------------
StatElecSolver: Electrostatics solver:
StatElecSolver: -------------------------------------
StatElecSolver: Electrostatic iteration: 1
StatElecSolver: Assembly (s) : 0.33295299999999994
10 0.3391E-02
20 0.9472E-04
30 0.7795E-07
37 0.4059E-10
ComputeChange: NS (ITER=1) (NRM,RELC): ( 0.88460910 2.0000000 ) :: electrostatics
StatElecSolver: Solve (s) : 0.22230700000000003
StatElecSolver: Tot. Electric Energy : 1.0818499242750658E-013
StatElecSolver: Capacitance : 2.1636998485501316E-013
StatElecSolver: Result Norm : 0.88460909986281633
StatElecSolver: Relative Change : 2.0000000000000000
StatElecSolver: Electrostatic iteration: 2
StatElecSolver: Assembly (s) : 0.29112699999999991
1 0.2896E-10
ComputeChange: NS (ITER=2) (NRM,RELC): ( 0.88460910 0.27968334E-09 ) :: electrostatics
StatElecSolver: Solve (s) : 1.9309999999999938E-002
StatElecSolver: Tot. Electric Energy : 1.0818499242750922E-013
StatElecSolver: Capacitance : 2.1636998485501843E-013
StatElecSolver: Result Norm : 0.88460909961540590
StatElecSolver: Relative Change : 2.7968333759297845E-010
ComputeChange: SS (ITER=1) (NRM,RELC): ( 0.88460910 2.0000000 ) :: electrostatics
Code: Select all
ComputeNorm: Computing norm of solution
ComputeChange: NS (ITER=1) (NRM,RELC): ( 0.93286628 2.0000000 ) :: stat elec solver
StatElecSolver: Solve (s) : 5.5589000000000333E-002
StatElecSolver: Tot. Electric Energy : 1.0825058661990775E-010
StatElecSolver: Potential difference: 1.0000000000000000
StatElecSolver: Capacitance : 2.1650117323981551E-010
StatElecSolver: Result Norm : 0.93286628081974932
StatElecSolver: Relative Change : 2.0000000000000000
DefaultFinish: Finished solver: stat elec solver
ComputeNorm: Computing norm of solution
ComputeChange: SS (ITER=1) (NRM,RELC): ( 0.93286628 2.0000000 ) :: stat elec solver
SingleSolver: Attempting to call solver: 2
SingleSolver: Solver Equation string is: electric force
StatElecForce: Computing electric force on boundaries
StatElecForce:
StatElecForce: Net electric force : -1.025385E-12 -1.071612E-12 -1.030866E-10
StatElecForce: Resultant force : 1.030973E-10
SingleSolver: Attempting to call solver: 3
Code: Select all
OS: Debian GNU/Linux 11 (bullseye) (X-Cinnamon/lightdm-xsession)
Word size of FreeCAD: 64-bit
Version: 0.20.2.29603 (Git) AppImage
Build type: Release
Branch: (HEAD detached at 0.20.2)
Hash: 930dd9a76203a3260b1e6256c70c1c3cad8c5cb8
Python 3.10.8, Qt 5.15.4, Coin 4.0.0, Vtk 9.1.0, OCC 7.6.3
Locale: French/France (fr_FR)
Installed mods:
* fasteners 0.4.52
* ThreadProfile 1.84.0