Sound diffraction by a slit existing between two half infinite planes

摘要

This paper deals with the problem of sound diffraction by the slit which exists between two half infinite planes. The planes are located between a point source and a receiver in the arrangement that the edges of the planes are in parallel holding certain distance. At first, a rather complicated formula to predict the amount of diffraction effect is derived based on Keller's geometrical theory of diffraction almost exactly. Secondly an approximate formula, simpler and more practical, is derived from the above formula. Calculated values from these two formulae are almost the same. The results of calculation using the formulae agreed well with the results of calculation using a boundary element method in two dimensions.