Form factor for identical, parallel, opposite rectangles F1-2 -- Algorithm 3.12

The form factors given by algorithms 3.12 and 3.13 are used in estimating the mean inter-reflected illuminances on the surfaces of rectangular rooms.

Input

Parameters X & Y where

as in diagram

Equation

Note

Angles are expressed in radians

Source

Siegel(1)

References

1. Siegel R and Howell J R Thermal Radiation Heat Transfer (New York: McGraw Hill) (1972)