Effects of departures from periodicity on the frequency domain and short pulse acoustic scattering from finite soft and rigid flat strip arrays.

Many structures of interest contain regularly spaced elements that leave their imprint on the acoustic scattered field. For periodic arrangements, even a few elements may imprint on the scattered field the signature of the periodic structure Floquet modes that characterize an infinite array [L. Carin and L. B. Felsen, J. Acoust. Soc. Am. 90, 2355(A) (1991)]. Explored here, for various collections of flat, soft, and rigid strip scatterers, is how departures from periodicity due to array truncation, as well as displacement, change in size, etc., of individual and groups of elements affects the time‐harmonic and short pulse plane wave scattered response. Reference solutions obtained numerically by direct integration of a (spectral domain)–(moment method) procedure are interpreted phenomenologically through asymptotic reductions to yield truncation edge diffracted contributions, local Floquet modes from the overall bulk of the array, and individual scatterings from displaced elements. The contracting behavior...