Short pulse sound-wave scattering from variously arranged multiple rigid flat strips in a fluid.

Abstract

In a companion paper (Felsen etal., previous paper), short pulse (SP) plane-wave sound scattering from an infinite plane periodic array of rigid flat strips in a fluid is analyzed via an observable-based parametrization (OBP) that highlights the temporal evolution of the global effects of periodicity from initially well-resolved local multiple scatterings. This temporal buildup is explored here further by treating directly a finite number of strips that may be noncoplanar and have unequal size and spacing. Such a model allows study of the physical size of the local environment that suffices to simulate the effects of infinite global periodicity, and it also permits assessment of how deviations from periodicity deteriorate the wave behavior of the ideal strictly periodic configuration. The reference solution is generated via the frequency domain from a multiple scattering integral equation algorithm implemented numerically by moment methods and novel asymptotics. The resulting data are then interpreted and reconstructed by TD-OBP that homes in directly on observed features in the scattered signal. Parametric studies, associated with wave-oriented signal processing in a phase space, furnish insight into the wave phenomena operative under the stated conditions. [Work supported by ONR.]