Acoustic field around a planar object levitated in an ultrasound waveguide

Abstract

This paper investigates acoustic levitation and noncontact transportation techniques for use with planar objects. An acoustic levitation system was developed that consists of a 1-mm-thick and 400-mm-long bending plate along with two bolt-clamped Langevin-type transducers (BLTs) that have stepped horns. A plane reflector was installed parallel to the vibrating plate to generate an ultrasound standing wave between the reflector and the plate. A planar object was levitated along the nodal line of the acoustic standing wave in the waveguide, and that affected the sound pressure distribution around the plate. The sound pressure distribution in the ultrasound waveguide was calculated via finite element analysis to investigate the effects of levitation of a planar object in the standing wave field. The (3, 1) resonance mode with a wavelength of approximately 15 mm in the x direction was excited in the air layer above and below the planar object. The acoustic field in the waveguide was sensitive to the length of the planar object, and several peaks occurred in the sound pressure amplitude when the half-wavelength resonance mode in the z direction was generated in the waveguide, indicating that there were suitable lengths of the plate for the acoustic levitation.This paper investigates acoustic levitation and noncontact transportation techniques for use with planar objects. An acoustic levitation system was developed that consists of a 1-mm-thick and 400-mm-long bending plate along with two bolt-clamped Langevin-type transducers (BLTs) that have stepped horns. A plane reflector was installed parallel to the vibrating plate to generate an ultrasound standing wave between the reflector and the plate. A planar object was levitated along the nodal line of the acoustic standing wave in the waveguide, and that affected the sound pressure distribution around the plate. The sound pressure distribution in the ultrasound waveguide was calculated via finite element analysis to investigate the effects of levitation of a planar object in the standing wave field. The (3, 1) resonance mode with a wavelength of approximately 15 mm in the x direction was excited in the air layer above and below the planar object. The acoustic field in the waveguide was sensitive to the length of ...