Broadband bistatic scattering from an array of regulary spaced cylinders

Abstract

Acoustic scattering by an array of regularly spaced cylinders in water tank has been investigated both theoretically and experimentally in order to evaluate the interference of scattered field. We carried out broadband bistatic scattering measurement for various pulse length over the frequency range 0.6 < ka < 2.7 including Rayleigh and Geometrical scattering region and the azimuthal angle (0~360°). Target strength(TS) for a group of cylinder is calculated based upon the infinite cylinder scattering model [1] which uses scattering directivity and phase difference and it includes interference of scattered field between cylinders. Measured TS were capable of describing fluctuations of calculated TS in azimuthal angles and frequencies that the usual incoherent summation never produces such fluctuations. Also, the scattering patterns corresponding to azimuthal angles and frequencies reflect the Bragg scattering. In particular, the fact that regular patterns appeared in side-scattering (90°) is very much correlated with scatterer spacing suggest that an inverse estimation of scatter spacing may be possible by measuring the bistatic scattered field. Copyright © (2010) by the International Congress on Acoustics.