On the validity of the wedge assemblage method for pressure-release sinusoids

Abstract

In the past, the wedge assemblage (WA) method for calculating the acoustic scattering from rough, long-crested, or corrugated surfaces has been compared with both experimental data and exact theory with good results. Nevertheless, significant questions about what physics is included in the method and its realm of validity remain unanswered. In this paper, the WA method is applied to scattering from pressure-release sinusoidal surfaces in order to further explore these topics. Comparisons with accurate benchmark calculations are carried out over a broad range of kh and kΛ (k is the acoustic wave number; h and Λ are the amplitude and wavelength of the sinusoid, respectively) indicate that the primary limitation of the WA method stems from its current failure to include multiple scattering effects. It is also shown that quite good agreement with the benchmark can be achieved by a ‘‘diffraction-only’’ WA model even when kh≪1 and ‘‘reflection-like’’ scattering patterns are observed.