Acoustic scattering from double infinite concentric cylindrical shells in water

Acoustic scattering from submerged double infinite concentric cylindrical shell insonified by incident plane wave is studied. The analytic solutions of scattering field are derived using elastic thin shell theory and Fourier transform. The scattering form functions of the single shell and double concentric shells insonified by a normally and obliquely incident plane wave are calculated. The results show that in cases of different incident angles, the scattering waves present different features because some different elastic wave types are excited. Generally, a combination of the outer shell, the inner shell and the coupling water layer between two shells dominate the scattering features of the double shells. When the outer shell is thinner and the inner shell is thicker, the low frequency scattering characteristics of the double infinite concentric cylindrical shells are dominated by the inner shell whether the incidence is normal or oblique. But the resonance of outer shell can't be neglected.