Scattering by penetrable acoustic targets
The method of matched asymptotic expansions (M.A.E.) is used to obtain asymptotic expansion of the solutions of the scattering by penetrable acoustic targets (density \(\rho_ t)\) immersed in fluid (density \(\rho_ a)\). The parameter is \(\epsilon =\rho_ a/\rho_ t\). The outer and inner expansions correspond to the incident frequencies being far or near to the resonant frequencies, respectively. The far field expressions for the scattered fields, including the total cross-sections, that are obtained from M.A.E. and from partial expansion of the solution are in close agreement for sufficiently small values of \(\epsilon\). Furthermore, an asymptotic approximation is obtained for the scattered field that is uniformly valid in the incident frequency which is not obtained by nuclear resonance theory.
scientific article; zbMATH DE number 3926526