Acoustic scattering from fluid-filled finite cylindrical shell in water:Ⅰ.theory

Acoustic scattering from a submerged fluid-filled finite cylindrical shell insonified by an incident plane wave is studied.The analytic solutions of the scattering field are derived using the elastic thin shell theory with the boundary conditions.The fluid-filled impedance adds to the impedance of the system due to the effect of internal fluid.The results show that in the backscattering field,rigid scattering has a large contribution only on the broadside and elastic scattering play a major role when oblique incidence.The dispersion curves of the phase velocity show that except the contribution by longitudinal wave and shear wave near the broadside a series of the additional waves caused by the internal fluid are added which have great contribution to the scattering field.Bowl-shape resonance curves are presented in the frequency-angle spectrum as the contribution of the internal fluid-added wave.