On articulated plates with micro-slits to tackle low-frequency noise

On articulated plates with micro-slits to tackle low-frequency noise

Blog Article

In recent years, new concepts of acoustic absorbers dedicated to the reduction of low-frequency noise have been developed.Among them, liners with moving parts, such as membrane-based liners, have been an object of particular interest.In the present paper, we propose a liner concept based on a cantilever beam made of articulated plates with micro-slits.Compared to membrane technologies, these micro-slits APS SALON KIT introduce a small leakage from the backing cavity that reduces the high compressibility effects occurring at very low frequencies in a small cavity.An acoustic liner including an ensemble of such articulated plates has been fabricated and characterized for grazing acoustic incidence in L-Lysine absence and in presence of flow.

Measurements in an impedance tube at normal incidence have also been performed, and perfect absorption is obtained at a frequency where the liner thickness corresponds to 1/16th of the acoustic wavelength.A new and simple model is proposed to predict the attenuation of this type of acoustic treatment.The results are in good agreement with the measurements, indicating a correct identification of the physical phenomena here at stake.