farFieldBC

Absorbing boundary condition for harmonic electromagnetic analysis

Since R2023a

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Description

A farFieldBC object specifies the thickness of an absorbing region as well as the exponent and scaling parameter defining the attenuation rate of the waves entering the absorbing region. edgeBC and faceBC objects contain farFieldBC objects in their FarField property.

Creation

Syntax

ffbc = farFieldBC(Name=Value)

Description

ffbc = farFieldBC(Name=Value) creates a farFieldBC object and sets properties using one or more name-value arguments. You must specify the thickness value. Specifying the exponent and scaling values is optional.

example

Properties

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Width of the far field absorbing region, specified as a positive number. The solver uses an absorbing boundary condition for a harmonic analysis.

Data Types: double

Exponent defining the attenuation rate of the waves entering the absorbing region, specified as a positive number. The solver uses an absorbing boundary condition for a harmonic analysis.

Data Types: double

Scaling parameter defining the attenuation rate of the waves entering the absorbing region, specified as a positive number. The solver uses an absorbing boundary condition for a harmonic analysis.

Data Types: double

Examples

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Open Live Script

Specify an absorbing boundary condition for an femodel object representing a harmonic electromagnetic problem.

Create an femodel object for solving a harmonic electromagnetic problem with an electric field type. Assign a geometry representing a 2-D plate with a hole to the model.

model = femodel(AnalysisType="electricHarmonic", ...
                Geometry="PlateHolePlanar.stl");

Plot the geometry with the edge labels.

pdegplot(model.Geometry,EdgeLabels="on");
xlim([-1 11])
ylim([-1 21])

Figure contains an axes object. The axes object contains an object of type line.

Specify an electric field on the circular edge.

model.EdgeBC(5) = edgeBC(ElectricField=[10 0]);
model.EdgeBC
ans = 
  1×5 edgeBC array

Properties for analysis type: electricHarmonic

Index    ElectricField    FarField
  1           []             []   
  2           []             []   
  3           []             []   
  4           []             []   
  5         [10 0]           []   

  Show all properties

Specify absorbing regions with a thickness of 2 on the edges of the rectangle. Use the default attenuation rate for the absorbing regions.

ffbc = farFieldBC(Thickness=2);
model.EdgeBC(1:4) = edgeBC(FarField=ffbc);
model.EdgeBC
ans = 
  1×5 edgeBC array

Properties for analysis type: electricHarmonic

Index    ElectricField        FarField    
  1           []          [1×1 farFieldBC]
  2           []          [1×1 farFieldBC]
  3           []          [1×1 farFieldBC]
  4           []          [1×1 farFieldBC]
  5         [10 0]               []       

  Show all properties

Check the parameters of the absorbing region for edge 1.

model.EdgeBC(1).FarField
ans = 
  farFieldBC with properties:

    Thickness: 2
     Exponent: 4
      Scaling: 5

Now specify the attenuation rate for the absorbing regions.

ffbc = farFieldBC(Thickness=2,Exponent=3,Scaling=100);
model.EdgeBC(1:4) = edgeBC(FarField=ffbc);
model.EdgeBC(1).FarField
ans = 
  farFieldBC with properties:

    Thickness: 2
     Exponent: 3
      Scaling: 100
Open Live Script

Specify an absorbing boundary condition for an femodel object representing a harmonic electromagnetic problem.

Create an femodel object for solving a harmonic electromagnetic problem with an electric field type. Assign a geometry representing a 3-D plate with a hole to the model.

model = femodel(AnalysisType="electricHarmonic", ...
                Geometry="PlateHoleSolid.stl");

Plot the geometry with the face labels.

pdegplot(model.Geometry,FaceLabels="on", ...
                        FaceAlpha=0.4);

Figure contains an axes object. The axes object contains 6 objects of type quiver, text, patch, line.

Specify the electric field on the circular face.

model.FaceBC(7) = faceBC(ElectricField=[10 0 0]);
model.FaceBC
ans = 
  1×7 faceBC array

Properties for analysis type: electricHarmonic

Index    ElectricField    FarField
  1           []             []   
  2           []             []   
  3           []             []   
  4           []             []   
  5           []             []   
  6           []             []   
  7        [10 0 0]          []   

  Show all properties

Specify absorbing regions with a thickness of 2 on the sides of the plate. Use the default attenuation rate for the absorbing regions.

ffbc = farFieldBC(Thickness=2);
model.FaceBC(3:6) = faceBC(FarField=ffbc);
model.FaceBC
ans = 
  1×7 faceBC array

Properties for analysis type: electricHarmonic

Index    ElectricField        FarField    
  1           []                 []       
  2           []                 []       
  3           []          [1×1 farFieldBC]
  4           []          [1×1 farFieldBC]
  5           []          [1×1 farFieldBC]
  6           []          [1×1 farFieldBC]
  7        [10 0 0]              []       

  Show all properties

Check the parameters of the absorbing region for face 6.

model.FaceBC(6).FarField
ans = 
  farFieldBC with properties:

    Thickness: 2
     Exponent: 4
      Scaling: 5

Now specify the attenuation rate for the absorbing regions.

ffbc = farFieldBC(Thickness=2,Exponent=3,Scaling=100);
model.FaceBC(3:6) = faceBC(FarField=ffbc);
model.FaceBC(6).FarField
ans = 
  farFieldBC with properties:

    Thickness: 2
     Exponent: 3
      Scaling: 100

References

[1] Larson, M.G. and Bengzon, F. The Finite Element Method: Theory, Implementation, and Applications. Springer Berlin, Heidelberg, 2013.

Version History

Introduced in R2023a

See Also

Objects