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Hybrid passive-active multilayer sound absorbers


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Cobo, Pedro, Doutres, Olivier, Fernandez, Alejandro and Siguero, M.. 2003. « Hybrid passive-active multilayer sound absorbers ». In 5th European Conference on Noise Control (Naples, Italy, May 19-21, 2003)

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A two-layer passive/active system to provide broadband absorption, including low frequencies, is described. The passive system consists of a fibrous layer in front of an air layer. Absorption at low frequencies is achieved by an active controller which drives an actuator in the back of the system that minimizes the pressure measured by a sensor in the air layer. The passive/active system is modelled considering plane waves propagating at oblique incidence. The absorbing layer is characterized by empirical equations of the nondimensional parameter En=ρ0f/σn, σn being the flow resistivity, f the frequency, and ρ0 the air density. The model predicts high performance of the hybrid passive-active system for values of R=σn d /Z0 close to 1.2, d being the thickness of the absorbing layer and Z0 the air impedance.

Item Type: Conference proceeding
Additional Information: Le résumé de la conférence est disponible à la page S54 de la revue Acta Acustica united with Acustica, vol. 89, suppl.
Doutres, Olivier
Affiliation: Autres
Date Deposited: 29 Oct 2014 17:57
Last Modified: 29 Nov 2017 19:37

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