Ultrasonic-driven synthetic-jet actuator: High-efficiency actuator creating high-speed and high-frequency pulsed jet

In this study, a new synthetic-jet actuator called ultrasonic-driven synthetic-jet (USDSJ) actuator is proposed. The actuator is composed of a fixed flat plate with a 1.0-mm-diameter orifice and a vibrating flat surface driven by an ultrasonic transducer. A jet created by the actuator is visualized by the schlieren method using a high-speed camera changing the height of the gap between the flat plate and vibrating surface from 300 mu m to 800 mu m. It is observed in the time-sequential schlieren images that a pulsed jet is created by the actuator at a high frequency of 19.7 kHz and the jet velocity is estimated from the images. It is found that the estimated jet velocity reaches 150 m/s and the velocity is linearly proportional to the vibrating-surface amplitude normalized by the height of the gap in the range of the normalized amplitudes smaller than-0.38. It is also found that the energy consumed per pulse in the proposed actuator is only less than 3% of that in the plasma synthetic-jet actuator when both ac-tuators produces the same jets in size and velocity.

Automated summary

This study introduces a new synthetic-jet actuator, called ultrasonic-driven synthetic-jet (USDSJ) actuator, which consists of a fixed flat plate and a vibrating flat surface driven by an ultrasonic transducer. The jet created by the actuator is visualized using the schlieren method and it is found that a pulsed jet is created at a high frequency of 19.7 kHz. The estimated jet velocity reaches 150 m/s and is linearly proportional to the vibrating-surface amplitude normalized by the height of the gap.