水中气泡之间的声相互作用

单个气泡的声衰减的实验结果可以用热传导粘滞和辐射损失来解释,但对于气泡层中(这里有许多气泡)的实验来说,上述机理却不能解释。因为根据这些机理算得的理论值比实验值小很多,这一问题三十多年来尚未解决。本文考虑气泡之间的声相互作用,算得的相互作用场和原始入射场有90°的相位差,这等效于在每个气泡上附加了一项阻力,从而使其阻尼增大很多。应用本文理论与上述实验结果比较,两者符合得很好。本文理论也指出,声相互作用并不改变气泡的共振频率,只是使其共振曲线展宽。当声波频率低于共振频率时,气泡的伴振质量增大,劲度减小。当频率高于共振频率时,情况则相反。 关键词：

SOUND INTERACTION AMONG BUBBLES IN WATER

As well known, the measurements of the sound attenuation on a single bubble can be explained by thermal conductivity, viscousity and radiation losses. But when the measurements were made in a bubble screen, it will not be so simple. Since the theoretical loss is much less than the measured one, this problem is open until now.In this paper, taking the sound interaction among bubbles in water into account, a 90 phasor between the primary incident sound and the multi-scattering sound has been ob-tained. The latter is equivalent to a retard force acting on every bubble, and they suffer an additional damping.Comparing our theory with Carstensen and Foldy's experiments, a satisfactory agreement has been, found. In addition, we point out that the resonant frequencies of bubbles do not vary with the interaction among them, but the resonant curves will be widened. When the sound frequency is lower than the resonant frequency of a bubble, the mass which accompanies it will get an increase and the stiffness get a decrease. When the sound frequency is higher than its resonant frequency, the situation will be converse.