# Electronically Steerable Ultrasound-Driven Air Stream

## TL;DR

This paper introduces a method to generate and electronically steer a focused air flow using ultrasound Bessel beams created by a phased array, enabling precise control of airflow in free space.

## Contribution

The authors develop a novel technique for creating steerable, ultrasound-driven air streams with high spatial and temporal resolution using an active phased array.

## Key findings

- Successfully generated and steered air flows using ultrasound Bessel beams.
- Demonstrated immediate formation and control of airflow after sound field generation.
- Achieved improved spatial and temporal resolution over traditional methods.

## Abstract

We have created a stretching air flow by generating a Bessel beam of ultrasound with an active phased array of acoustic transducers in free space. The generated Bessel beam is electronically steerable in terms of its position and direction of propagation. The fastest spot in the flow could be located apart from the sound source itself. The flow is formed immediately after the sound field is generated, which can be electronically accomplished with the phased array that we fabricated. We formulate the basic technique for realizing such air-borne flows and experimentally describe their physical properties. Our technique would be capable of controlling the air flow in free-space with an improved temporal and spatial resolution compared with those conventionally considered.