Abstract

A method of control for an ordered group of particles that levitate in an ultrasonic field and structures of rectilinear segments is proposed. An ultrasonic field in air at a frequency of 40 kHz and particles whose dimensions are less than a quarter of a wavelength or thin cylindrical objects with diameters of less than a quarter of a wavelength are considered. The ultrasonic field is formed using four phased arrays of radiators that are placed oppositely on lateral faces of a rectangular parallelepiped. The radiators form a distribution of the standing wave field in the plane, which provides levitation of particles in a rectangular grid in a plane layer. With the use of numerical simulation and experimentally, it has been shown that the obtained distribution is stabilized and the particles remain immobile at local minimums of the Gor’kov potential. Moreover, regulation of the phase difference of opposite radiators provides controlled motion of a group of particles in a horizontal plane and a change in the focusing plane of side radiators provides controlled motion of a group of particles along the vertical plane. It has been shown experimentally that not only small particles but also structures assembled of rectilinear segments whose length is much greater than the wavelength can levitate in this field distribution.

中文翻译：

---

超声场中粒子和直线结构的有序群的悬浮和控制

摘要

提出了一种控制在超声场中悬浮的有序粒子群和直线段结构的控制方法。考虑了空气中频率为40 kHz的超声场和尺寸小于波长四分之一的颗粒或直径小于波长四分之一的细圆柱体。超声波场是使用辐射体的四个相控阵形成的，辐射体在长方体的侧面相对放置。辐射器在平面内形成驻波场的分布，从而在平面层的矩形网格中提供粒子的悬浮。通过数值模拟和实验，已经表明，所获得的分布是稳定的，并且颗粒在戈尔科夫势的局部最小值处保持不动。此外，对相对辐射器的相差的调节提供了一组粒子在水平面内的受控运动，而侧面辐射器的聚焦平面的变化提供了一组粒子在垂直平面内的受控运动。实验证明，在这种场分布中，不仅小颗粒而且由长度远大于波长的直线段组装而成的结构也可以悬浮。相对辐射器的相位差的调节提供了一组粒子在水平面内的受控运动，而侧面辐射器的聚焦平面的变化提供了一组粒子在垂直平面内的受控运动。实验证明，在这种场分布中，不仅小颗粒而且由长度远大于波长的直线段组装而成的结构也可以悬浮。相对辐射器的相位差的调节提供了一组粒子在水平面内的受控运动，而侧面辐射器的聚焦平面的变化提供了一组粒子在垂直平面内的受控运动。实验表明，在这种场分布中，不仅小颗粒而且由长度远大于波长的直线段组装而成的结构也可以悬浮。