Troubles in electric fieldcomputing on a 2 bodies model

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tbossis
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Troubles in electric fieldcomputing on a 2 bodies model

Post by tbossis »

Hi everybody, i'm trying to compute the electric field in a "box" of air at room temperature (first body), with 0 V on one end and 1 V on the other end of the box. Inside this box, there is a second body which is a conductor with also 0 V applied on its boundary condition. My problem is that the potential applied on the conductor seems to be ok inside the volume of the conductor but it doesn't affect the potential inside body filled with air.

Here is the .sif file I used :

Code: Select all

Header
  CHECK KEYWORDS Warn
  Mesh DB "." "."
  Include Path ""
  Results Directory ""
End

Simulation
  Max Output Level = 5
  Coordinate System = Cartesian
  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 = detecteur.sif
  Post File = detecteur.vtu
Output File = wf_map.result
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

Solver 1
  Equation = Electrostatics
  Calculate Electric Energy = True
  Calculate Electric Field = True
  Calculate Electric Flux = True
  Variable = Potential
  Procedure = "StatElecSolve" "StatElecSolver"
  Exec Solver = Always
  Stabilize = True
  Bubbles = False
  Lumped Mass Matrix = False
  Optimize Bandwidth = False
  Steady State Convergence Tolerance = 5.0e-7
  Nonlinear System Convergence Tolerance = 1.0e-10
  Nonlinear System Max Iterations = 100000
  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 = 100000
  Linear System Convergence Tolerance = 1.0e-10
  BiCGstabl polynomial degree = 2
  Linear System Preconditioning = ILU1
  Linear System ILUT Tolerance = 1.0e-3
  Linear System Abort Not Converged = True
  Linear System Residual Output = 10
  Linear System Precondition Recompute = 1
End

Equation 1
  Name = "Equation 1"
  Active Solvers(1) = 1
End

Material 1
  Name = "Air (room temperature)"
  Viscosity = 1.983e-5
  Heat expansion Coefficient = 3.43e-3
  Heat Conductivity = 0.0257
  Relative Permittivity = 1.00059
  Sound speed = 343.0
  Heat Capacity = 1005.0
  Density = 1.205
End

Material 2
  Name = "Copper (generic)"
  Heat expansion Coefficient = 16.5e-6
  Heat Conductivity = 401.0
  Sound speed = 3810.0
  Heat Capacity = 385.0
  Mesh Poisson ratio = 0.34
  Relative Permittivity = 1e10
  Density = 8960.0
  Poisson ratio = 0.34
  Youngs modulus = 115.0e9
End

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

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

Boundary Condition 1
  Target Boundaries(1) = 1
  Name = "Side1"
End

Boundary Condition 2
  Target Boundaries(1) = 2
  Name = "Side2"
End

Boundary Condition 3
  Target Boundaries(1) = 3
  Name = "Side3"
  Periodic BC = 1
End

Boundary Condition 4
  Target Boundaries(1) = 4
  Name = "Side4"
  Periodic BC = 2
End

Boundary Condition 5
  Target Boundaries(1) = 5
  Name = "Pad"
  Potential = 1
End

Boundary Condition 6
  Target Boundaries(1) = 6
  Name = "Grid"
  Potential = 0
End

Boundary Condition 7
   Target Boundaries(1) = 7
   Name = "Drift"
   Potential = 0
End
Here is how it should looks like :
Image

But here is how it actually looks like :
Image

Does anyone have any idea what I could have done wrong ?

Regards,
Theo
raback
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Re: Troubles in electric fieldcomputing on a 2 bodies model

Post by raback »

Probably your different bodies are not joined at the interfaces since you can visualize discontinuous fields. So it is a meshing issue. -Peter
tbossis
Posts: 2
Joined: 10 Aug 2020, 16:12
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Re: Troubles in electric fieldcomputing on a 2 bodies model

Post by tbossis »

Thank you peter, I managed to solve the problem in GMSH.

Regards,
Theo
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