A simple scattering model for finite objects

A model for acoustic scattering from finite objects is described in terms of a three‐dimensional Fourier wave space. This wave space representation, adapted from x‐ray diffraction analysis, provides a convenient method for depicting aspect and frequency dependence simultaneously. Physical observables are interpreted by means of the Ewald construction. The method is illustrated for a rigid right circular cylinder. A procedure which eliminates mathematical difficulties which arise from surface discontinuities for finite objects when one‐dimensional models are employed is discussed. Incorporation of impedance boundary conditions can alter details of the cylinder's scattering cross section. Examples are discussed and illustrated for aluminum and brass cylinders in water. Dominant observed features are related to the large phase shift which occurs at the shear critical angle. The model provides a useful simulation tool and also suggests a method for analyzing experimental data in detail.