Directional acoustic underwater thruster

This paper described a novel directional underwater thruster which could change thrust directions without any moving parts. When the underwater thruster moved along a non-vertical angle, it could produce straight backward thrust of 2.3mN and lateral thrust of 0.6mN in parallel on the device surface, with the total thrust/weight ration of 2:1. Water jet was streamed out by high intensity acoustic beam due to acoustic streaming effect to push the device itself oppositely. To enhance the acoustic streaming effect, a self-focusing acoustic transducer (SFAT) with air reflectors was used to focus the acoustic beam.