Development of a compact sound source for the active control of turbofan inlet noise

The concept of a compact sound source driven by piezoactuators is experimentally investigated, and analytical design tools are developed. The sound source, consisting of a thin, cylindrically curved aluminum panel and a pair of collocated, surface-bonded piezoceramic actuators, was developed with the objective of employing it as a secondary sound source in the active control of turbofan blade interaction inlet noise. The sound source was fitted in an experimental duct representative of an aircraft engine inlet, and the interior and exterior sound pressure levels generated by the source were measured. The effects of excitation voltage, excitation frequency, duct length, and downstream termination of the duct were investigated. It was found that the source is capable of generating relatively high acoustic levels at its fundamental frequency (over 130 dB at maximum voltage input). Techniques for analytically predicting the acoustic levels are investigated. A commercial code for numerical modeling of structural-acoustic radiation was utilized. Results show generally good agreement with experimental measurements for the case of the short duct. It is believed that the model accuracy can be further improved through additional refinements in the modeling techniques.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Mechanical Engineering

Department dc:contributor.department

Mechanical Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1992

Author dc:creator

• Dungan, Mary E.

Chairs dc:contributor.committeechair

• O'Brien, Walter F. Jr.
• Fuller, Christopher R.

Committee member dc:contributor.committeemember

• Cudney, Harley H.

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

etd-03302010-020615

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/41872