Development and Initial Evaluation of an Acoustic Apparatus Used For Testing of Farfield Noise Emitted by a Propeller in a Short Duct

<p>The purpose of this thesis was to design, construct and evaluate an apparatus which was used for testing of acoustic emissions by a propeller in a short duct. An apparatus was designed based on a combination of acoustic principles and a desire to be able apply the knowledge gained to a practical application such as an ultralight aircraft in an effort to reduce the overall noise levels emitted. The apparatus consisted of a 35 horsepower ultralight engine, a four bladed ultralight propeller, and a duct constructed of a foam core covered with fiberglass. Initial evaluations compared noise levels from the apparatus both with and without the shroud in place, as well as various engine silencer configurations. The data gathered proved the apparatus was actually about 6 dB louder with the shroud than without the shroud as a result of strong rotor-stator interactions. Based on the initial evaluations, this apparatus demonstrated its potential for further testing and acoustical work in the principles of rotor-stator interactions, short duct acoustics, and active noise control applications with the long range goal being to reduce the acoustic emissions from propeller driven aircraft.</p>

Name thesis:degree_name

Master of Science in Aerospace Engineering

Level thesis:degree_level

Thesis - Open Access

Discipline thesis:degree_discipline

Aerospace Engineering

Year

1997

Author dc:creator

• Oleson, R. Duane

Contributors dc:contributor

• H.V.L. Patrick
• Allen I. Ormsbee
• Charles N. Eastlake

• acoustic emissions
• propeller
• farfield
• short duct
• Aerospace Engineering

Repository record dc:identifier

https://commons.erau.edu/db-theses/245

OAI identifier oai:identifier

oai:commons.erau.edu:db-theses-1225