acoustic bubbles driven actuator for remote energy scavenging in a liquid medium

this paper presents a new type of an acoustic energy scavenging system utilizing a miniature rotor actuated by acoustically oscillating bubbles periodically vibrates piezocantilevers to generate electric power. the behavior of an oscillating bubble under acoustic excitation and the oscillating bubble-induced microstreaming are experimentally investigated to prove the working principle of the proposed acoustically driven actuator. the motion of the acoustically driven actuator and the electric voltage generated from the vibrating piezocantilever are investigated. the rotating speed of the actuator is highly dependent on the applied acoustic frequency and inversely proportional to the distance between acoustic transmitters. the output voltages and power generated from the vibrating piezocantilever are measured using the custom-made electrical circuit with different electric loads. furthermore, the effect of multiple piezocantilevers on the electric energy density is investigated to demonstrate the possibility of improving the electric energy density. this actuation technique is a simple but useful tool for energy scavenging and for potential acoustic wave sensors and actuators.