An analytic approach to sound scattering from a pair of scatterers with application to rigid spheres

As a first step towards investigating multiple scattering of acoustic waves by a few scatterers, this paper presents a detailed study of the case that sound is scattered by a pair of arbitrary targets. An intuitive scheme is developed for calculating the effective scattering function. An approximate formula is derived and presented in a simple form. To verify the approach, it is applied to the special case of two rigid spheres, as the exact solut ion exists for this special situation. It is shown that the approximate res ults compare favorably with that from the exact solution for a wide range o f situations. Through the comparison, the validity range of the approximate approach is inferred. Some ambiguities in the previously published results are also pointed out.