An analytical theory is developed for acoustic streaming induced by an acoustic wave field inside and outside a spherical fluid particle, which can be a liquid droplet or a gas bubble. The particle is assumed to undergo the monopole (pulsation) and the dipole (translation) oscillation modes. The dispersed phase and the carrier medium are considered to be immiscible, compressible, and viscous. The developed theory allows one to calculate the acoustic streaming both outside and inside the fluid particle. In contrast to earlier works, no restrictions are imposed on the thickness of the outer and inner viscous boundary layers with respect to the particle radius. A numerical implementation of the obtained analytical results is used to evaluate the acoustic streaming for different experimentally relevant configurations, such as an air bubble in water, a water droplet in oil, and a water droplet in air, considering both traveling and standing acoustic waves. The results show the richness of streaming pattern variations that arise in bubbles and droplets.

中文翻译：

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流体粒子内部和外部的声学流，它们经历单极和偶极子振荡。

针对由球形流体颗粒内部和外部的声波场引起的声流发展了一种解析理论，该球形流体颗粒可以是液滴或气泡。假定粒子经历了单极（脉冲）和偶极（平移）振荡模式。分散相和载体介质被认为是不溶混的，可压缩的和粘稠的。发达的理论允许人们计算流体颗粒内部和外部的声流。与早期的工作相反，相对于颗粒半径，外部和内部粘性边界层的厚度没有限制。所获得分析结果的数值实现用于评估不同实验相关配置（例如水中的气泡，考虑到行进的声波和驻波声波，油中的水滴和空气中的水滴。结果表明，气泡和液滴中出现的流态变化丰富。