Aeroacoustics of perforated drag plates for quiet transport aircraft

Historically aircraft noise is one of the principal environmental issues for aviation. Within this context, the Silent Aircraft Initiative was launched with the objective to achieve a step-change in noise reduction compared to current practice. One of the most critical tasks in noise reduction is to develop technologies to increase drag in quiet ways. The work presented in this thesis focuses primarily on aeroacoustic tests and analysis of perforated drag plates. The idea behind a quiet spoiler or drag rudder is to alter the noise production mechanism by perforating the drag plates. The hypothesis is that the large length scales responsible for the noise radiated by unsteady vortical structures can be changed to small length scales driving jet noise at frequencies which are perceived unannoying by the human ear. The aeroacoustic characteristics of laboratory-scale perforated spoilers were measured in an acoustic chamber at MIT. Based on the experimental data a noise prediction model was developed for the bluff-body and turbulent mixing noise generated by a perforated drag rudder. Acoustic phased array measurements of seven perforated plates in four different installation configurations were conducted in the Markham wind tunnel at Cambridge University to further investigate the noise mechanisms.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2005

Author dc:creator

• Sakaliyski, Kiril Dimitrov

Advisor dc:contributor.advisor

• Zoltan Spakovszky.

• Aeronautics and Astronautics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/33212

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/33212