Intl. Cooperation Ctr. for Sci. and Technol., Tokyo Inst. of Technol., O-okayama, Meguro-ku, Tokyo 153, Japan
In order to analyze the sound field near a corner of a rigid wedge, the virtual discontinuity principle of diffraction (VDPD) that has been proposed and the representation of the sound field that satisfies both the wave equation and boundary conditions that can be constituted by this principle [J. Acoust. Soc. Am. 95, 2354--2362 (1994)] is applied to this problem. Then the sound pressure on the rigid surface can be expressed as an integral of the particle velocity normal to an extension line of one of the wedge surfaces where a point of interest is located on it. On the other hand, the particle velocity at any field point can be expressed as an integral of the sound pressure along the rigid surface using the Green's theorem. Thus there are two relations between the sound pressure on the rigid surface and the particle velocity normal to the extension lines of the wedge. Analyzing these two relations near the corner of the wedge, the diffraction process that occurs near the corner becomes clear. Its good understanding will surely help in understanding the nature of waves diffracted by a polygon.