Transparent and fixed boundariesΒΆ

Learning targets

  • Specify fixed boundary conditions for a 3D computational domain
  • Non-rectangular computational domains

This geometry example specifies a rectangular computational domain with fixed boundary identifiers on the y==0 and x==0 planes and with transparent boundaries otherwhere. This is a typical situation for light scattering simulations with periodic, mirror-symmetrical scattering objects where the size of the computational domain can be reduced by a factor of 4 when symmetry considerations about the geometry and the source (e.g., plane wave at perpendicular incidence) are taken into account. Please compare examples 3D Periodic boundaries I and 2D Transparent and fixed boundaries. The resulting geometry and mesh in different views correspond to the following figure:

_images/figure_360.png

.jcm Input File

  • layout.jcm [ASCII]

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    Layout3D {
  Name = "TutorialExample3D"
  UnitOfLength = 1e-6
  MeshOptions {    
    MinimumMeshAngle = 20
    MaximumSideLength = 0.75
  }
  Extrusion {
    Objects {
      Polygon { 
        Name = "ComputationalDomain/Background" 
        DomainId = 101 
        Priority = -1 
        Points = [0 0, 2 0, 2 2, 0 2] 
        Boundary { 
          Number = 1 
          Class = Domain
          BoundaryId = 1
        } 
        Boundary { 
          Number = [ 2 3]
          Class = Transparent
        }         
        Boundary { 
          Number = 4
          Class = Domain
          BoundaryId = 2
        } 
      } 
      Polygon {  
        Name = "Diamond_for_extrusion"  
        DomainId = 102 
        Priority = 1 
        Points = [0 -1.5, 1.2 0, 0 1.5, -1.2 0]
      } 
      Circle {
        Name = "Circle_for_extrusion"
        DomainId = 103
        Priority = 2
        Radius = 0.5
        RefineAll = 1
        MeshOptions{
          MaximumSideLength = 0.4
        }
      }
    }
    MultiLayer {
      LayerInterface {
        BoundaryClass = Transparent
      }
      Layer {
        Thickness = 0.5
        DomainId = 1
      }
      Layer {
        Thickness = 0.75
        DomainIdMapping = [101 2, 102 3, 103 3]
      }
      Layer {
        Thickness = 0.4
        DomainIdMapping = [101 2, 102 2, 103 4]
      }
      Layer {
        Thickness = 0.4
        DomainIdMapping = [101 2, 102 2, 103 2]
      }
      LayerInterface {
        BoundaryClass = Transparent
      }
    }  
  }
}