Institute of Mechanical Systems, Department of Mechanical and Process Engineering, ETH Zentrum, CH-8092 Zurich, Switzerland.
Lab Chip. 2012 Oct 21;12(20):4010-21. doi: 10.1039/c2lc40733g.
Acoustic radiation forces are increasingly used for the handling of micron sized particles (cells, functionalized beads, etc.) suspended in a fluid in the chamber of a manipulation device. The primary radiation forces arise as a nonlinear effect when an acoustic wave interacts with a particle. For specific robotic applications, precise control of the acoustic field in the cavity is important, which is excited, for example, by piezoelectric transducers attached to the device. Based on Gor'kov's potential the relevant forces on spherical particles can be computed. The field can be controlled by varying the excitation parameters: chamber and electrode configuration, as well as frequency, amplitude and phase of the excitation and their modulation. In the first part of the present tutorial, a number of examples are described: displacement and rotation of particles in micro machined chambers and macroscopic transport of particles in a larger chamber. In the second part, numerical tools (Finite Volume Method, COMSOL) are used to model the interaction of the acoustic field with a particle beyond a Gor'kov potential: viscosity, effects of walls near particles and acoustic radiation torque to rotate the particle. Excellent agreement between the various methods has been found.
声辐射力越来越多地用于处理悬浮在微操作装置腔室内的流体中的微米级颗粒（细胞、功能化珠等）。当声波与颗粒相互作用时，主要的辐射力会产生非线性效应。对于特定的机器人应用，腔室内的声场的精确控制很重要，例如通过附着在装置上的压电换能器来激发。基于戈尔科夫势，可以计算球形颗粒上的相关力。可以通过改变激励参数来控制场：腔室和电极配置，以及激励的频率、幅度和相位及其调制。在本教程的第一部分，描述了一些示例：微加工腔室内的颗粒位移和旋转以及较大腔室内的颗粒宏观运输。在第二部分，使用数值工具（有限体积法、COMSOL）来模拟声场与颗粒的相互作用，超越戈尔科夫势：粘度、颗粒附近壁面的影响以及声辐射扭矩以旋转颗粒。已经发现各种方法之间具有极好的一致性。
