弹性波由吸收圆柱的散射  

Scattering of elastic wave by an absorbing cylinder

作　　者：刘银斌[1] 

机构地区：[1]中国科学院声学研究所,北京1000080

出　　处：《声学学报》1998年第6期481-489,共9页Acta Acustica

基　　金：国家自然科学基金

摘　　要：研究了弹性纵波照射粘弹圆柱产生的稳态散射，导出了简洁的散射场解析表达式，数值计算了吸收和非吸收圆柱散射作的散射截面。结果表明，对高速圆柱散射体，散射截面随Ka增加是光滑振荡变化的，吸收圆柱和非吸收圆柱散射截面特征类似。对低速圆柱散射体，振荡变化的散射截面上叠加有一系列狭窄峰，散射圆柱和周围介质的对应速度差别越大，这种狭窄峰也越多，越靠近极值附近，这些狭窄峰越密，圆柱存在吸收衰减时将降低这些狭窄峰。当散射圆柱和周围介质对应的纵波速度和横波速度差别很小时，散射截面为非规则的小幅度的谐振。The steady-state scattering of compressional wave (P-wave) by an absorbing cylinde ris investigated. The simple expressions for the scattered field caused by a normally incident plane P-wave are derived. The scattering cross sections for both non-absorbing and absorbing cylinders are calculated. Results show that for high velocity cylinder scatterer, the curves of scattering cross sections are smooth and oscillatory with ka, and the calculating scattering cross sections for non-absorbing and absorbing cylinders exhibit similar behavior. For low velocity cylinder scatterer, it can be seen from the scattering cross sections that a number of narrow peaks superimpose on a smooth background. The more the difference in c0rresponding velocity in the two media is, the more the peaks are5 the nearer the values of maximum and minimumare, the denser the narrow peaks are, and the peaks will be decreased by the absorbing effects of cylinder. The scattering cross sections are small irregular oscillation while the corresponding velocity difference between the scattering cylinder and the matrix media is very small.

关 键 词：声波 纵波 散射截面 弹性波 散射场 解析解 

分 类 号：O422.5[理学—声学]