摘要
分析有限声波束从平面液-固界面上散射的困难主要发生在平面波反射系数的处理上。本文应用奇异点展开法将反射系数在Rayleigh极点附近展开成一个解析函数(其值为1)和Laurent展开式之和。散射场的计算用波数和界面两个变量的双重积分来进行,常数1产生刚性界面的几何散射波,Rayleigh极点展开项导致Rayleigh泄漏波。本文特别证明,对于大多数液-固界面,极点的留数近似地正比于极点的虚部。因此,根据复极点的值可以确定Rayleigh泄漏波的整个特性,包括激发和再辐射效率。对于反向散射场,既然负Rayleigh极点起作用,自然地出现反向Rayleigh泄漏波。
For scattering of a bounded acoustic beam from a liquid-solid interface, the principal difficulty comes from the treatment of tie plane wave reflection coefficient. In the present paper, following the Singularity Expansion Method, we expand the reflection coifficient into the sum of an analytic function (constant 1) and the principal part of the Laurent expansion in a neighborhood of the Rayleigh pole. The scattered field is now evaluated by a double integral in the wave number and interface planes. The constant 1 produces a rigid boundary geometrical reflected beam, and the expansions at the Rayleigh poles yield the leaky Rayleigh waves. It is particularly proved that the residues of the poles are nearly proportional to the imaginary parts of the poles for most liquid-solid interfaces. Therefore, the complex pole may determine the whole behavior of the leaky Rayleigh wave, including the excitation and reradiation efficiencies. For the backscattered field, since the negative Rayleigh pole plays a major role, a backward leaky Rayleigh wave will appear naturally.
出处
《声学学报》
EI
CSCD
北大核心
1990年第6期437-449,共13页
Acta Acustica
