Rapid rise of planar object by near-field acoustic levitation on recessed acoustic radiation surface

Near-field acoustic levitation (NFAL) can be observed for a planar object placed on the vibrating surface of a longitudinal vibrator. However, for a vibrating surface with a recess, not only NFAL was observed, but also jumping behavior with a snapping sound. This phenomenon was examined analytically and experimentally with bolt-clamped Langevin transducers and a duralumin vibratory horn. Jumping occurred when the minimum value of the acoustic radiation force was larger than the weight of the object. The snapping sound during jumping was generated by the sound pressure that was focused at the center of the bottom surface of the object when the acoustic radiation force peaked due to acoustic resonance in the recessed space.

Automated summary

NFAL can create levitation for a planar object on the vibrating surface, while a vibrating surface with a recess can lead to jumping behavior accompanied by a snapping sound. Jumping occurs when the minimum value of the acoustic radiation force exceeds the weight of the object, and the snapping sound is generated by focused sound pressure due to acoustic resonance in the recessed space.