水中双层无限长圆柱壳体声散射

研究水下双层无限长圆柱壳体的声散射。采用弹性薄壳理论和Fourier变换方法导出了散射声场的解析解。并分别计算了平面波正横和斜入射单层和双层无限长圆柱壳体的远场散射形态函数。计算表明在不同的入射角,由于不同类型的弹性波被激励,散射波呈现不同的特性。通常双层无限长圆柱壳体的散射特性由外壳、内壳和中间耦合水层共同作用决定。但外壳很薄、内壳较厚、水层较薄时,无限长充水双层圆柱壳体的低频散射特性主要由单层内壳决定。当然这时外壳的共振特性也不能忽略。

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.