Symmetry for Surface-to-Surface Radiation
Use this node to calculate view factors on only a part of a symmetric geometry to improve efficiency, by defining either one symmetry plane in 2D, 2D axisymmetric, and 3D components, multiple perpendicular symmetry planes in 2D and 3D components; or sectors of symmetry in 2D and 3D components. In addition, a reflection plane can be defined inside each sector of symmetry. Table 6-7 summarizes the available options for each dimension.
Table 6-7: Options for symmetry definition, example with 5 sectors.
Symmetry Type
2D
2D axisymmetric
3D
One Plane
Two Planes
Not applicable
Three Planes
Not applicable
Not applicable
Sectors
Not applicable
Sectors and Reflection
Not applicable
Symmetry for Surface-to-Surface Radiation
Depending on component’s dimension, select the Type of symmetry to be defined:
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In 2D components, select between Plane of symmetry (default), Two perpendicular planes of symmetry, or Sectors of symmetry.
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In 2D axisymmetric components, only the Plane of symmetry option is available.
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In 3D components, select between Plane of symmetry (default), Two perpendicular planes of symmetry, Three perpendicular planes of symmetry, or Sectors of symmetry.
Depending on the Type of symmetry selected from the list and on the dimension, further settings are required.
When Apply symmetry to external radiation sources is selected (default), all external radiation sources are duplicated with respect to the symmetry condition. Otherwise, the external radiation sources do not follow the symmetry condition.
Plane of Symmetry
The coordinates of the points defining the plane should be set:
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In 2D components, the symmetry plane is defined by two points. If the Selection method is Coordinates, set the x and y coordinates of the First point on plane of reflection and of the Second point on plane of reflection. Else, if the Selection method is Point Selection, you can directly select the points from the Graphics window. In the Selection of First Point and Selection of Second Point sections, first use the Active button to toggle between turning ON and OFF selections, that is, making the selections active for that selection list. Then select the points from the Graphics window.
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In 2D axisymmetric components, the symmetry plane is parallel to the z=0 plane. If the Selection method is Coordinates, set the z coordinate of plane of reflection, zsym. Else, if the Selection method is Point Selection, you can directly select the point from the Graphics window. In the Selection of the Point Defining the Plane of Reflection section, first use the Active button to toggle between turning ON and OFF selections, that is, making the selection active for that selection list. Then select the point from the Graphics window.
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In 3D components, the symmetry plane is defined by three points. If the Selection method is Coordinates, set the x, y, and z coordinates of the First point on plane of reflection, the Second point on plane of reflection, and the Third point on plane of reflection. Else, if the Selection method is Point Selection, you can directly select the points from the Graphics window. In the Selection of First Point, Selection of Second Point, and Selection of Third Point sections, first use the Active button to toggle between turning ON and OFF selections, that is, making the selections active for that selection list. Then select the points from the Graphics window.
The Show the plane of symmetry check box is selected by default. Clear it to hide the plane in the Graphics window.
Two Perpendicular Planes of Symmetry
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In 2D components, the planes intersection line is along the out-of-plane direction. The Point at the intersection of symmetry planes and the Rotation angle from Cartesian axis, θ, should be defined.
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In 3D components, the Planes intersection line can be set Along the x-axis, Along the y-axis, or Along the z-axis. A Point at the intersection of symmetry planes and the Rotation angle from Cartesian axis, θ, should be defined. The position of the point along the intersection line can be arbitrary as it does not change the planes definition. The direction of the angle θ can be checked in the figure displayed below the settings, for each case of alignment of the intersection line.
The Show the planes of symmetry check box is selected by default. Clear it to hide the planes in the Graphics window.
Three Perpendicular Planes of Symmetry
The planes are parallel to the Cartesian axis. Only the Point at the intersection of symmetry planes should be defined.
The Show the planes of symmetry check box is selected by default. Clear it to hide the planes in the Graphics window.
Sectors of Symmetry
The coordinates of the points defining the symmetry axis should be set:
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In 2D components, the symmetry axis is the out-of-plane vector, and the center of the symmetry must be defined. Set the x and y coordinates of the Point of central symmetry.
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In 3D components, the symmetry axis is defined by two points. Set the x, y, and z coordinates of the First point defining sector symmetry axis and the Second point defining sector symmetry axis.
Enter a value for the Number of sectors. This should be a numerical value greater or equal to 2.
If the Reflection for symmetrical sector check box is selected, set the coordinates of the Radial direction of reflection plane, u. This option can be used when each sector has itself a plane of symmetry.
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The Surface-to-Surface Radiation Interface
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Theory for Surface-to-Surface Radiation
Location in User Interface
Context Menus
Surface-to-Surface Radiation>Symmetry for Surface-to-Surface Radiation
Ribbon
Physics tab with Surface-to-Surface Radiation selected:
Global>Symmetry for Surface-to-Surface Radiation