Ultrasonic trapping of small particles by a vibrating rod

In this paper, the ultrasonic trapping of small particles by a vibrating rod is proposed and analyzed. An aluminum rod, which is driven by an actuator and operates in the 0th order vibration mode (back and forth vibration mode), can trap small particles in water. The experimental phenomena and the trapping mechanism are theoretically analyzed, and the acoustic radiation force acting on a spherical particle near the surface of the vibrating rod is estimated. The effects of operating frequency, rod radius, particle radius and other physical parameters are investigated experimentally and theoretically, and useful guidelines to optimize the trapping capability are proposed.