Experimental analysis of the particle oscillations in acoustic levitation

The objective of this paper is to investigate the spontaneous particle oscillations that occur in a single-axis acoustic levitator. A high speed camera was used to record the particle oscillations of spheres and a tracking algorithm was implemented in Matlab to obtain the sphere position as a function of time. A FFT analysis was applied to obtain the frequencies of the particle oscillations in both axial and radial directions. The frequencies of the particle oscillations were compared with the theoretical frequencies, which were obtained by a theoretical model that assumes that the oscillations of the levitated sphere can be described by a spring-mass system.