Skip to main content

About this book

This book systematically introduces readers to the fundamental physics and a broad range of applications of acoustic levitation, one of the most promising techniques for the container-free handling of small solid particles and liquid droplets. As it does away with the need for solid walls and can easily be incorporated into analysis instruments, acoustic levitation has attracted considerable research interest in many fields, from fluid physics to material science.

The book offers a comprehensive overview of acoustic levitation, including the history of acoustic radiation force; the design and development of acoustic levitators; the technology’s applications, ranging from drop dynamics studies to bio/chemical analysis; and the insightful perspectives that the technique provides. It also discusses the latest advances in the field, from experiments to numerical simulations. As such, the book provides readers with a clearer understanding of acoustic levitation, while also stimulating new research areas for scientists and engineers in physics, chemistry, biology, medicine and other related fields.

Table of Contents


Chapter 1. Dialogues on Levitation Techniques and Acoustic Levitation

This chapter is in the form of dialogues which took place at three different scenarios. In the dialogues, the fundamental principle, applications and future directions of acoustic levitation as well as the comparison with other levitation techniques are discussed.
Duyang Zang

Chapter 2. Standing Waves for Acoustic Levitation

Standing waves are the most popular method to achieve acoustic trapping. Particles with greater acoustic impedance than the propagation medium will be trapped at the pressure nodes of a standing wave. Acoustic trapping can be used to hold particles of various materials and sizes, without the need of a close-loop controlling system. Acoustic levitation is a helpful and versatile tool for biomaterials and chemistry, with applications in spectroscopy and lab-on-a-droplet procedures. In this chapter, multiple methods are presented to simulate the acoustic field generated by one or multiple emitters. From the acoustic field, models such as the Gor’kov potential or the Flux Integral are applied to calculate the force exerted on the levitated particles. The position and angle of the acoustic emitters play a fundamental role, thus we analyse commonly used configurations such as emitter and reflector, two opposed emitters, or arrangements using phased arrays.
Asier Marzo

Chapter 3. Design of Single-Axis Acoustic Levitators

In this chapter, a numerical procedure based on the finite element method (FEM) is presented for simulating and designing single-axis acoustic levitators. We first present an overview of the equations governing the propagation of mechanical waves in solids, piezoelectric materials and the air medium. We then show how axisymmetric models based on FEM can be utilized for simulating piezoelectric transducers and the acoustic cavity of the levitator. To illustrate the design procedure, the finite element method is applied to simulate and design a 25-kHz bolt-clamped Langevin-type transducer. The FEM is also used to design a resonant single-axis acoustic levitator and to investigate the behavior of a non-resonant acoustic levitator.
Marco A. B. Andrade

Chapter 4. Lattice Boltzmann Method for Acoustics Levitation

In this chapter, a novel computational method for flow, lattice Boltzmann method, is introduced. We first present the fundamentals and general implements of the method, followed by non-reflective boundary condition techniques, which is important for acoustic simulations. The von Neumann analysis shows lattice Boltzmann method is promising for acoustic simulations. In the latter part of this chapter, we present the applications of lattice Boltzmann method on sound phenomena, such as aeroacoustics, non-linear sound effect and acoustic levitation.
Xiao-Peng Chen

Chapter 5. Dynamics of Acoustically Levitated Drops

Levitation of liquid droplet is one of the most important applications of acoustic levitation, not only for the study of fluid physics, but also for bio/chemical analysis. In this chapter, we review various behaviors of acoustically levitated drops, ranging from evolution of static equilibrium shape, oscillation, to different drop instabilities. We also discuss drop manipulation by using acoustic levitation. At last, we propose several possible future directions to stimulate multi-discipline researches based on the technique.
Zehui Zhang, Kangqi Liu, Duyang Zang

Chapter 6. Flow Fields and Heat Transfer Associated with an Acoustically Levitated Droplet

Considering the potential applications, a better understanding of the flow fields in an acoustically levitated droplet is of great significance in scientific fields. The flow generated by a nonlinear acoustic field is known as acoustic streaming. Using acoustic levitation, multi-scale acoustic streaming can be induced both inside and outside the droplet. In the internal flow field, the streaming configuration is affected by the physical properties of the droplet, i.e., the droplet diameter and rotation. The external flow field can be characterized by the applied sound pressure, physical properties of the droplet, and surrounding gas. These flow fields play an important role in the heat and mass transfer of the levitated droplet. This chapter provides a comprehensive review of the flow fields, the general theory of acoustic streaming, and an understanding of the heat transfer/mixing enhancement.
Koji Hasegawa

Chapter 7. Droplet Evaporation Under Acoustic Levitation

Droplet evaporation is a ubiquitous phenomenon widely existing in nature and spray-based industrial applications, such as liquid fuel power engines, pharmaceutical manufacturing, powder and food processing, and chemical industry.
Yanju Wei

Chapter 8. Crystallization in Acoustically Levitated Drops

Crystallization is a process of forming a phase with a highly ordered structure, in which the basic building units (atoms, molecules, or ions) are arranged in such a way that all units are positioned at 3D translationally periodic lattice. It is a very important process, and in that it produces crucial materials (crystals) that are indispensable for many industrial applications and scientific researches.
Da-Chuan Yin, Duyang Zang

Chapter 9. Applications of Acoustic Levitation in Chemical Analysis and Biochemistry

The acoustic levitation is a versatile tool that can be used to study physical, chemical, or biochemical characteristics of liquid samples. By acoustically levitating samples in single droplets, their chemical or biochemical analysis and reactions can be investigated in the container-less condition in the absence of interactions between samples and container walls in ambient air as well as in controlled environments. In this chapter, we describe experiments on the single-droplet chemical/biochemical analysis, a recently proposed application for protein crystallography experiments, and relate instrumentation developments.
Soichiro Tsujino, Takashi Tomizaki
Additional information

Premium Partner

    Image Credits