Aeroacoustics of a wall perforation in the pure grazing flow regime: effect of the perforation geometry
conference paper
Acoustical dampers are used in order to avoid the noise propagation. Well known examples are the aero-engine liners, the IC-engine exhaust muffers, and the liners in combustion chambers. These devices comprise wall perforations, responsible for their sound absorbing features. Understanding the effect of the flow on the acoustic properties of a perforation is essential for the design of acoustic dampers. In the present work the effect of grazing flow on the impedance of slit shaped wall perforations is experimentally investigated by means of a multi-microphone impedance tube. Measurements are carried out for perforations with different geometries. The focus of the experiments is on the Strouhal number dependence of the acoustic impedance. An analytical model of the aeroacoustic behaviour of a two-dimensional wall perforation subject to grazing flow is proposed. These theoretical results are used to qualitatively explain the effect of the perforation geometry on its acoustic absorption properties. © 2012 by the American Institute of Aeronautics and Astronautics, Inc.
TNO Identifier
476233
ISBN
9781600869327
Source title
18th AIAA/CEAS Aeroacoustics Conference 2012 (33rd AIAA Aeroacoustics Conference), 4-6 June 2012, Colorado Springs, Colorado, USA
Collation
12 p.
Files
To receive the publication files, please send an e-mail request to TNO Repository.