Oscillation characteristics of levitated sample in resonant acoustic field

This study aims to improve and investigate the levitation stability and mechanism of restoring force on an acoustically levitated droplet. To better understand the stable manipulation conditions of a droplet in an acoustic levitator, we experimentally investigated the unsteady translational motion of the acoustically levitated droplet. Furthermore, we visualized its translational motion in the horizontal and vertical (x and y) directions using a high-speed video-camera and estimated the dynamics of a droplet using four distinct levitated samples. The ratio of the levitated samples’ translational frequency, which is obtained by dividing the frequency in the y direction, fy, with that in the x direction, fx, was 3.4, which is equal to the restoring force coefficients. We found that our experimental data agree with the calculation results of a previous study. Our insights could pave the way to manipulate the dynamic behavior of a levitated sample for achieving more stable levitation.