ZHENG Guoyin FAN Jun TANG Weilin

(State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University Shanghai 200240)

Received Nov. 10, 2009

Revised Dec. 1, 2009

Abstract  Acoustic scattering from a submerged fluid-filled finite cylindrical shell insonified by an incident plane wave was studied. The analytic solutions of the scattering field are derived using the elastic thin shell theory with the boundary conditions. The fluid-filled impedance, due to the effect of internal fluid, must add to the impedance of the system. 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 comparing with the internal vacuum condition, except the contribution by longitudinal wave and shear wave near the broadside a series of the additional waves caused by the internal fluid is added which have great contribution to the scattering field. Bowlshape resonance curves are presented in the frequency-angle spectrum as the contribution of the internal fluid waves.

PACS numbers: 43.30, 43.20