Diffraction Sound Fields Around a Polygonal Cylinder and a Circular Cylinder

抄録

An approximate expression for multiple-edge diffraction of sound sound a polygonal cylinder is derived based on Pierce's approximate expression for sound diffracted by a single wedge barrier. This expression is actually applied to the computation of the diffraction field around a hexagonal cylinder, which is also obtained experimentally through a sound visualization method using three color-light-emitting diodes. The hexagonal cylinder model used in this experiment has a circular aperture on its side surface and a speaker inside. A circular cylinder model is also used. It is, moreover, investigated whether or not the diffraction field around a circular cylinder may be estimated using the hexagonal cylinder inscribed in it. It is whose that the computed results agree well with the visualized ones, and that the diffraction field around a circular cylinder can be approximately estimated using the hexagonal cylinder inscribed in it.