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 symmetry (default), Two perpendicular symmetry planes, or Sector symmetry.
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In 2D axisymmetric components, only the Plane symmetry option is available.
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In 3D components, select between Plane symmetry (default), Two perpendicular symmetry planes, Three perpendicular symmetry planes, or Sector 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 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 defining reflection plane and of the Second point defining reflection plane. Else, if the Selection method is Point selection, you can directly select the points from the Graphics window. In the First Point Defining Reflection Plane and Second Point Defining Reflection Plane 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 Reflection plan position, zsym. Else, if the Selection method is Point selection, you can directly select the point from the Graphics window. In the First Point Defining Reflection Plane section, first use the Active button to toggle between turning ON and OFF selection, that is, making the selection active. 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 defining reflection plane, the Second point defining reflection plane, and the Third point defining reflection plane. Else, if the Selection method is Point selection, you can directly select the points from the Graphics window. In the First Point Defining Reflection Plane, Second Point Defining Reflection Plane, and Third Point Defining Reflection Plane 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 symmetry plane checkbox is selected by default. Clear it to hide the plane in the Graphics window.
Two Perpendicular Symmetry Planes
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In 2D components, the planes intersection line is along the out-of-plane direction. The Point at intersection of symmetry planes and the Rotation angle from Cartesian axis, θ, should be defined. If the Selection method is Coordinates, set the x and y coordinates of the Point at intersection of symmetry planes. Else, if the Selection method is Point selection, you can directly select the point from the Graphics window. In the Point at Intersection of Symmetry Planes section, first use the Active button to toggle between turning ON and OFF selection, that is, making the selection active. Then select the point from the Graphics window.
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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 the intersection of symmetry planes and the Rotation angle from Cartesian axis, θ, should be defined. If the Selection method is Coordinates, set the x, y, and z coordinates of the Point at intersection of symmetry planes. Else, if the Selection method is Point selection, you can directly select the point from the Graphics window. In the Point at Intersection of Symmetry Planes section, first use the Active button to toggle between turning ON and OFF selection, that is, making the selection active. Then select the point from the Graphics window.
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 symmetry planes checkbox is selected by default. Clear it to hide the planes in the Graphics window.
Three Perpendicular Symmetry Planes
The planes are parallel to the Cartesian axis. Only the Point at intersection of symmetry planes should be defined. If the Selection method is Coordinates, set the x, y, and z coordinates of the Point at intersection of symmetry planes. Else, if the Selection method is Point selection, you can directly select the point from the Graphics window. In the Point at Intersection of Symmetry Planes section, first use the Active button to toggle between turning ON and OFF selection, that is, making the selection active. Then select the point from the Graphics window.
The Show symmetry planes checkbox is selected by default. Clear it to hide the planes in the Graphics window.
Sector 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. If the Selection method is Coordinates, set the x and y coordinates of the Point defining central symmetry. Else, if the Selection method is Point selection, you can directly select the point from the Graphics window. In the Point Defining Central Symmetry section, first use the Active button to toggle between turning ON and OFF selection, that is, making the selection active. Then select the point from the Graphics window.
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In 3D components, the symmetry axis is defined by two points. If the Selection method is Coordinates, set the x, y, and z coordinates of the First point defining sector symmetry axis and of the Second point defining sector symmetry axis. Else, if the Selection method is Point selection, you can directly select the points from the Graphics window. In the First Point Defining Sector Symmetry Axis and Second Point Defining Sector Symmetry Axis 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.
Enter a value for the Number of sectors. This should be a numerical value greater or equal to 2.
The Show symmetry axis checkbox is selected by default. Clear it to hide the axis in the Graphics window.
If the Reflection for symmetrical sector checkbox 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