Acoustic jet based on acoustic metamaterial

TL;DR

This paper introduces a new gradient index acoustic metamaterial inspired by optical lenses, capable of generating ultra-long acoustic jets from near to far field, with potential applications in acoustic focusing.

Contribution

The paper presents the design and numerical demonstration of a novel MGLL-based acoustic metamaterial that extends acoustic jet length from near to far field, surpassing previous limitations.

Findings

Achieved acoustic jets with length up to 30λ.

Demonstrated capability of MGLL to focus acoustic energy over extended distances.

Validated the design through numerical simulations.

Abstract

In this paper, a novel gradient index (GRIN) acoustic metamaterial is proposed based on the concept of optical modified generalized Luneburg lens (MGLL). With the MGLL, double-foci and high energy density between the two foci can be achieved, which enables the realization of an ultra-long acoustic jet between the two foci. Compared to the generalized Luneburg lens with a single focus, which can only achieve short acoustic jet in the near field or ultra-long acoustic jet in the far field, the proposed MGLL can achieve an acoustic jet extending from the near field to the far field. This capability of the MGLL is theoretically and numerically demonstrated. Furthermore, acoustic metamaterial based MGLL is designed with lattice unit cells having a variable filling ratio. Numerical simulation results show that ultra-long acoustic jets can be achieved with a jet length of up to 30{\lambda} , covering both the near field and the far field.