Dynamics of a spherical particle in an acoustic field: A multiscale approach
Dynamics of a spherical particle in an acoustic field: A multiscale approach
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声场中球形粒子的动力学：多尺度方法
DOI：
10.1063/1.4896523
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发表时间：
2014
影响因子：
4.6
通讯作者：
J. Vanneste
中科院分区：
文献类型：
--
作者：
Jin;J. Vanneste
声波场中的刚性球形粒子以波周期振荡，但也具有较长时间尺度上的平均运动。这种平均运动的动力学对于声学微流体的许多应用至关重要，包括粒子操纵和流动可视化。它由四种物理效应控制：声（辐射）压力、流动、惯性和粘性阻力。在本文中，我们进行了系统的多尺度分析的问题，以评估这些影响的相对重要性取决于系统的参数，包括波的振幅，波长，声速，球半径和粘度。我们确定了两个杰出的制度，其特征在于三个四种效果之间的平衡，我们推导出的方程，管理在每个政权的平均粒子运动。这恢复并组织了King的经典结果[“On the acoustic radiation pressure on spheres，”Proc. R. Soc.A147，212-240（1934）]，戈尔'kov [“在一个理想的流体中的声场中作用在一个小颗粒上的力，”Sov. Phys.6，773-775（1962）]和Doinikov [“Acoustic radiation pressure on a rigid sphere in a viscous fluid，”Proc.R. Soc.伦敦A447，447-466（1994）]，阐明了这些结果的有效性范围，并揭示了一种新的非线性动力学机制。在这种情况下，颗粒的平均运动与周围流体的运动保持密切耦合，而粘度影响流体运动，但它对声压没有影响。简化的方程，有效时，只有两个物理效应控制的粒子运动，也推导出来。它们被用来获得充分条件的粒子作为一个被动示踪剂的拉格朗日平均流体运动。
A rigid spherical particle in an acoustic wave field oscillates at the wave period but has also a mean motion on a longer time scale. The dynamics of this mean motion is crucial for numerous applications of acoustic microfluidics, including particle manipulation and flow visualisation. It is controlled by four physical effects: acoustic (radiation) pressure, streaming, inertia, and viscous drag. In this paper, we carry out a systematic multiscale analysis of the problem in order to assess the relative importance of these effects depending on the parameters of the system that include wave amplitude, wavelength, sound speed, sphere radius, and viscosity. We identify two distinguished regimes characterised by a balance among three of the four effects, and we derive the equations that govern the mean particle motion in each regime. This recovers and organises classical results by King [“On the acoustic radiation pressure on spheres,” Proc. R. Soc. A147, 212–240 (1934)], Gor'kov [“On the forces acting on a small particle in an acoustical field in an ideal fluid,” Sov. Phys.6, 773–775 (1962)], and Doinikov [“Acoustic radiation pressure on a rigid sphere in a viscous fluid,” Proc. R. Soc. London A447, 447–466 (1994)], clarifies the range of validity of these results, and reveals a new nonlinear dynamical regime. In this regime, the mean motion of the particle remains intimately coupled to that of the surrounding fluid, and while viscosity affects the fluid motion, it plays no part in the acoustic pressure. Simplified equations, valid when only two physical effects control the particle motion, are also derived. They are used to obtain sufficient conditions for the particle to behave as a passive tracer of the Lagrangian-mean fluid motion.
DOI：
10.1098/rspa.2010.0457
发表时间：
2011-06-08
影响因子：
3.5
作者：
Vanneste, J.;Buehler, O.
通讯作者：
Buehler, O.