title: Acoustophoresis of disk-shaped microparticles: A numerical and experimental study of acoustic radiation forces and torques.
abstract: Disk-shaped microparticles experience an acoustic radiation force and torque in an ultrasonic standing wave. Hence, they are translated by the acoustic field, an effect called acoustophoresis, and rotated. The torque effect is also known from the "Rayleigh disk" which is described in literature for sound intensity measurements. In this paper, inviscid numerical simulations of acoustic radiation forces and torques for disks with radius ≪ wavelength in water are developed in good agreement with former analytical solutions, and the dependence on disk geometry, density, and orientation is discussed. Experiments with alumina disks (diameter 7.5 μm), suspended in an aqueous liquid in a silicon microchannel, confirm the theoretical results qualitatively at the microscale and ultrasonic frequencies around 2 MHz. These results can potentially be applied for the synthesis of disk-reinforced composite materials. The insights are also relevant for the acoustic handling of various disk-shaped particles, such as red blood cells.
authors.affiliation: Institute of Mechanical Systems (IMES), Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology (ETH Zurich), Tannenstrasse 3, CH-8092 Zurich, Switzerland.
authors.forename: Alexander
authors.initials: A
authors.lastname: Garbin
authors.affiliation: Institute of Mechanical Systems (IMES), Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology (ETH Zurich), Tannenstrasse 3, CH-8092 Zurich, Switzerland.
authors.forename: Ivo
authors.initials: I
authors.lastname: Leibacher
authors.affiliation: Institute of Mechanical Systems (IMES), Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology (ETH Zurich), Tannenstrasse 3, CH-8092 Zurich, Switzerland.
authors.forename: Philipp
authors.initials: P
authors.lastname: Hahn
authors.affiliation: Complex Materials, Department of Materials, Swiss Federal Institute of Technology (ETH Zurich), Vladimir-Prelog-Weg 5, CH-8093 Zurich, Switzerland.
authors.forename: Hortense
authors.initials: H
authors.lastname: Le Ferrand
authors.affiliation: Complex Materials, Department of Materials, Swiss Federal Institute of Technology (ETH Zurich), Vladimir-Prelog-Weg 5, CH-8093 Zurich, Switzerland.
authors.forename: André
authors.initials: A
authors.lastname: Studart
authors.affiliation: Institute of Mechanical Systems (IMES), Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology (ETH Zurich), Tannenstrasse 3, CH-8092 Zurich, Switzerland.
authors.forename: Jürg
authors.initials: J
authors.lastname: Dual
mesh_terms: D000465:Algorithms; D048430:Cell Shape; D055252:Cell-Derived Microparticles / Q000000981:diagnostic imaging* / Q000648:ultrastructure; D003198:Computer Simulation; D006801:Humans; D056656:Lab-On-A-Chip Devices; D046210:Microfluidic Analytical Techniques; D008954:Models, Biological; D013016:Sound; D019415:Torque; D014463:Ultrasonography