Loughborough University
Leicestershire, UK
LE11 3TU
+44 (0)1509 263171
Loughborough University

Loughborough University Institutional Repository

Please use this identifier to cite or link to this item: https://dspace.lboro.ac.uk/2134/18926

Title: Investigation of the acoustic black hole termination for sound waves propagating in cylindrical waveguides
Authors: Azbaid El Ouahabi, Abdelhalim
Krylov, Victor V.
O'Boy, D.J.
Issue Date: 2015
Publisher: © International Institute of Noise Control Engineering (I-INCE)
Citation: AZBAID EL OUAHABI, A., KRYLOV, V.V. and O'BOY, D.J., 2015. Investigation of the acoustic black hole termination for sound waves propagating in cylindrical waveguides. Presented at InterNoise 2015, 44th International Congress and Exposition on Noise Control Engineering, San Francisco, USA, 9-12 August.
Abstract: So far, acoustic black holes have been investigated mainly for flexural waves in thin plates for which the required linear or higher order reduction in wave velocity with distance can be easily achieved by changing the plate’s local thickness. In the present paper, the results of the experimental investigations of the acoustic black hole for sound absorption in air are described. To achieve the required power-law decrease in sound velocity with propagation distance the inhomogeneous acoustic waveguides earlier proposed by Mironov and Pislyakov (2002) and made of quasi-periodic ribbed structures have been manufactured to provide linear and quadratic decreases in acoustic wave velocity with distance. Measurements of the reflection coefficients for guided acoustic modes incident on the black holes have been carried out in the frequency range of 100-1000 Hz. Initial measurements were conducted without insertion of any absorbing materials. The results show the possibility of significant reduction of the acoustic reflection in this case. Addition of small pieces of absorbing porous materials caused further reduction in the reflection coefficients, albeit not as significant as it could be expected.
Description: This is a conference paper.
Sponsor: EPSRC grant EP/K038214/1
Version: Accepted for publication
URI: https://dspace.lboro.ac.uk/2134/18926
Appears in Collections:Conference Papers and Presentations (Aeronautical and Automotive Engineering)

Files associated with this item:

File Description SizeFormat
Azbaid et al InterNoise 2015.pdfAccepted version710.67 kBAdobe PDFView/Open

 

SFX Query

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.