
Proceedings Paper
Grazing incidence modeling of a metamaterial-inspired dual-resonance acoustic linerFormat | Member Price | Non-Member Price |
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Paper Abstract
To reduce the noise emitted by commercial aircraft turbofan engines, the inlet and aft nacelle ducts are lined with
acoustic absorbing structures called acoustic liners. Traditionally, these structures consist of a perforated facesheet
bonded on top of a honeycomb core. These traditional perforate over honeycomb core (POHC) liners create an
absorption spectra where the maximum absorption occurs at a frequency that is dictated by the depth of the honeycomb
core; which acts as a quarter-wave resonator. Recent advances in turbofan engine design have increased the need for thin
acoustic liners that are effective at low frequencies. One design that has been developed uses an acoustic metamaterial
architecture to improve the low frequency absorption. Specifically, the liner consists of an array of Helmholtz resonators
separated by quarter-wave volumes to create a dual-resonance acoustic liner. While previous work investigated the
acoustic behavior under normal incidence, this paper outlines the modeling and predicted transmission loss and
absorption of a dual-resonance acoustic metamaterial when subjected to grazing incidence sound.
Paper Details
Date Published: 28 March 2014
PDF: 10 pages
Proc. SPIE 9064, Health Monitoring of Structural and Biological Systems 2014, 906421 (28 March 2014); doi: 10.1117/12.2059834
Published in SPIE Proceedings Vol. 9064:
Health Monitoring of Structural and Biological Systems 2014
Tribikram Kundu, Editor(s)
PDF: 10 pages
Proc. SPIE 9064, Health Monitoring of Structural and Biological Systems 2014, 906421 (28 March 2014); doi: 10.1117/12.2059834
Show Author Affiliations
Benjamin S. Beck, National Institute of Aerospace (United States)
NASA Langley Research Ctr. (United States)
NASA Langley Research Ctr. (United States)
Published in SPIE Proceedings Vol. 9064:
Health Monitoring of Structural and Biological Systems 2014
Tribikram Kundu, Editor(s)
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