Analysis of circumferential waves on a water-filled cylindrical shell

The structure of scattering field from a water-filled cylindrical shell is studied.The analytic solutions of scattering field are derived using elastic thin shell theory and Sommerfeld-Watson Transformation (SWT) method.Complex wave-number poles of circumferential waves are found numerically,the phase speed and attenuation of circumferential waves between the situation of a hollow cylindrical shell and a water-filled cylindrical shell are compared.The synthesis of backscattering form functions which are sum of specular reflection component and circumferential waves is consistent with normal mode result.The computed echo's arrive time sequences of additional fluid circumferential waves are compared with experimental results.The results show that richer resonance peaks appeared in the form functions of a water-filled cylindrical shell and the formation of echo's structure are due to re-radiation effects of additional fluid circumferential waves.