平面声波斜入射到水中无限长圆柱壳体的纯弹性共振散射

斜入射情况下水中弹性圆柱壳体的共振声散射问题至今还很少被研究。本文导出了平面声波斜入射时水中无限长圆柱壳体纯弹性共振散射函数的简单而明显的表达式。针对中空铝圆柱壳体(b/a=0.8)详细计算了不同入射角时纯弹性共振散射的分波共振谱,同时还给出了远场反向散射形态函数及其刚硬背景隔离,发现形态函数受吻合频率的影响很大。文中详细计算了斜入射时无固次复频率平面上的共振复极点分布,并由此计算了不同入射角时各阶共振模式,特别是附加共振模式所对应螺旋环绕波的相速度频散曲线。这些结果十分有助于认识声波斜入射下圆柱壳体的共振和再辐射的物理本质。

Pure elastic resonance scattering of an obliquely incident plane acoustic wave by a submerged infinite cylindrical shell

Until now,sound resonance scattering by a submerged elastic cylindrical shell at oblique incidence has not been extensively studied.In this paper,we derive a simple and explicit expression of the pure elastic resonance scattering function of a submerged infinite cylindrical shell excited by a plane wave at oblique incidence.For backscattering of an aluminum tube (b/a=0.8) we have calculated (a) the partial resonance spectra at n=0-7,(b) the far field total form functions and the pure elastic resonance form functions,(c) the complex resonance poles in the normalized.complex.frequency plane,and (d) the dispersion curves of the first several families of belieal waves,at various in cident angles indetails.We find-that the coincidence frequency of the l=(1) wave plays a very important role.The results given here are very helpful to understand the physical nature of the resonance and reradiation of a submerged cylindrical shell excited by sound at oblique incidence.