Electronic Theses and Dissertations

Date of Award

2012

Document Type

Dissertation

Degree Name

M.S. in Engineering Science

Department

Mechanical Engineering

First Advisor

Nathan E. Murray

Second Advisor

Wayne E. Prather

Third Advisor

Elizabeth K. Ervin

Relational Format

dissertation/thesis

Abstract

Aerodynamic noise has been a problem since the first use of the jet engine for military aircraft in World War II. For further uses of the jet engine to be possible, problems due to jet noise must be researched and addressed. Anechoic chambers were proposed as a testing facility for research in aerodynamic noise because of their supposed free-field characteristics. The international standard ISO 3745-1977 was introduced to determine whether the facilities could be considered anechoic, semi-anechoic, or neither. An experiment was designed to determine at what frequencies the National Center for Physical Acoustics' Jet Lab Facility is non-anechoic, semi-anechoic, or anechoic. To comply with the guidelines of ISO 3745- 1977, three sources were designed and tested at frequencies from 25 Hz to 16000 Hz. The voltages were acquired at each frequency to calculate the sound pressure level and determine if the calculated values are within the allowed tolerance of the inverse square law.

Concentration/Emphasis

Emphasis: Aeroacoustics

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