Experimental demonstration of a space-time modulated airborne acoustic circulator

Fuente: arXiv
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Main Authors: Chen, Tinggui, Mallejac, Matthieu, Bi, Chuanxing, Xia, Baizhan, Fleury, Romain
Format: Preprint
Published: 2024
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author Chen, Tinggui
Mallejac, Matthieu
Bi, Chuanxing
Xia, Baizhan
Fleury, Romain
author_facet Chen, Tinggui
Mallejac, Matthieu
Bi, Chuanxing
Xia, Baizhan
Fleury, Romain
contents Achieving strongly nonreciprocal scattering in compact linear acoustic devices is a challenging task. One possible solution is the use of time-modulated resonators, however, their implementation in the realm of audible airborne acoustics is typically hindered by the difficulty to obtain large modulation depth and speeds while managing noise issues. Here, we propose a practical and cost-efficient route to realize simple modulated resonators and observe experimentally the strong nonreciprocal behavior of an acoustic circulator. We propose to modulate the neck cross-section areas of three coupled Helmholtz resonators using rotating circular plates actuated by an electrical motor, and control their phase difference via meshed gears, thereby implementing a modulation scheme with broken time-reversal symmetry that effectively imparts angular momentum to the system. We experimentally demonstrate tunable nonreciprocal behavior with a high nonreciprocal isolation of 34 dB and reflection as low as -9 dB, with insertion losses of 5 dB and parasitic signals below -20 dB. All the experimental results agree well with theoretical and numerical predictions.
format Preprint
id arxiv_https___arxiv_org_abs_2411_16057
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Experimental demonstration of a space-time modulated airborne acoustic circulator
Chen, Tinggui
Mallejac, Matthieu
Bi, Chuanxing
Xia, Baizhan
Fleury, Romain
Fluid Dynamics
Achieving strongly nonreciprocal scattering in compact linear acoustic devices is a challenging task. One possible solution is the use of time-modulated resonators, however, their implementation in the realm of audible airborne acoustics is typically hindered by the difficulty to obtain large modulation depth and speeds while managing noise issues. Here, we propose a practical and cost-efficient route to realize simple modulated resonators and observe experimentally the strong nonreciprocal behavior of an acoustic circulator. We propose to modulate the neck cross-section areas of three coupled Helmholtz resonators using rotating circular plates actuated by an electrical motor, and control their phase difference via meshed gears, thereby implementing a modulation scheme with broken time-reversal symmetry that effectively imparts angular momentum to the system. We experimentally demonstrate tunable nonreciprocal behavior with a high nonreciprocal isolation of 34 dB and reflection as low as -9 dB, with insertion losses of 5 dB and parasitic signals below -20 dB. All the experimental results agree well with theoretical and numerical predictions.
title Experimental demonstration of a space-time modulated airborne acoustic circulator
topic Fluid Dynamics
url https://arxiv.org/abs/2411.16057