1979 年 35 巻 10 号 p. 544-553
The uniform asymptotic solution derived by Kouyoumjian and Pathak for a spherical sound diffraction by a wedge of arbitrary angle and the two asymptotic solutions derived by Pierce are quantitatively compared with the rigorous integral solution developed by Wiegrefe, Macdonald, and Carslaw. Level difference between Kouyoumjian & Pathak's asymptotic solution and the rigorous solution is less than 0. 5dB for the wedge of arbitrary exterior angle νπ only if kr_sr/L≧0. 25π, here r_s and r are respectively the distances from the edge of the wedge to the source and the observating point and L is the shortest distance to the observating point from the source in stepping over the edge. On the other hand the approximation error of Pierce's first and second asymptotic solutions become greater as ν→1. However Pierce's second solution has less approximation error than Kouyoumjian & Pathak's solution for ν≦1. 4. For ν=2;namely a half plane the above three asymtotic solutions become a same expression which level difference from the rigorous solution is less than 0. 5dB only if kL≧0. 21π. The above mentioned is confirmed also by the experimental results.