球形粒子之间的声相互作用

本文讨论某种介质(其中包括许多球形粒子,例如浓悬浮体)对平面波的散射问题,计算了粒子之间的声相互作用场,从而得到了粒子的等效散射截面。当粒子大小比声波波长小很多时,可有如下的结论:(1)由于声相互作用,一个粒子的散射截面只有原来的Q倍,从几何上看,这是由于粒子的互相遮蔽的结果,其遮蔽因子为Q= |1-(γ₀A₀⁽¹⁾+γ₁A₁⁽¹⁾|²;(2)考虑到相互作用之后,散射系数与浓度不再是线性关系;(3)当粒子的尺度比声波波长小很多但比粘滞波波长大很多时,相互作用之后粒子的散射系数与频率的关系仍服从瑞利散射。但当粒子半径接近或小于粘滞波波长时,散射系数与频率的关系比四次方要高。关键词：

SOUND INTERACTION AMONG SPHERICAL PARTICLES

In this paper, we considered the scattering of a plane sound wave in a medium which contains many spherical particles, for example, a concentrated suspension in a liquid. The sound interaction field and the equivalent scattering cross section of a partical have been calculated. When dimensions of the particles are much less than the sound wave-length, the following conclusions can be drawn, a) On account of the interaction, the scattering cross section must have a multiplying factor Q. Geometrically, it is due to the masking effect on each other, and Q= |1-(γ₀A₀⁽¹⁾+γ＇₁A₁⁽¹⁾|² is called masking factor, b) The dependence of scattering coefficient on partical concentration is no longer a linear one. c) When the dimensions of them are much less than the sound wavelength but larger than viscous wavelength, the scattering coefficient of them will obey Rayleigh's law. But when their radii are near or less than viscous wavelength, the scattering co-efficients will show a dependence on frequency that is higher than the fourth power.