Visualizing Interior And Exterior Jet Aircraft Noise

<p>In today's competitive aerospace industry, the quest for quiet has drawn significant attention to both the interior and exterior design of an airplane. Understanding the noise generation mechanisms of a jet aircraft is a crucial first step toward developing the most cost-effective noise and vibrations abatement methods. In this investigation, the Helmholtz Equation Least Squares (HELS) based nearfield acoustic holography will be used to understand noise transmission caused by jet engine and turbulence into the fuselage of a jet aircraft cruising at 30,000 ft. </p> <p>Modern propulsive jet engines produce exterior noise sources with a high amplitude noise field and complicated characteristics, which makes them very difficult to characterize. In particular, there are turbulent eddies that are moving through the jet at high speeds along the jet boundary. These turbulent eddies in the shear layer produce a directional and frequency dependent noise. The original HELS approach assumes a spherical source at the origin and computes the acoustic field based on spherical emission from this source. This assumption of one source at the origin is not sufficient to characterize a complex source like a jet. As such, a modified HELS approach is introduced that will help improve the source characterization as it is not dependent on a single source at the origin but a number of virtual sources throughout the space. Custom microphones are created to take acoustic pressure measurements around the jet engine. These measured acoustic pressures are then taken as input to the modified HELS algorithm to visualize the noise pattern of a subsonic jet engine.</p>

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Open Access Dissertation

Discipline thesis:degree_discipline

Mechanical Engineering

Year dc:date.available

2014

Author dc:creator

• Moondra, Manmohan Singh

Contributors dc:contributor

• Sean F. Wu

• Aircraft Interior Noise
• HELS
• Jet Noise
• microphone arrays
• Nearfield Acoustic Holography
• Noise Imaging
• Acoustics, Dynamics, and Controls
• Mechanical Engineering

Repository record dc:identifier

https://digitalcommons.wayne.edu/oa_dissertations/906

OAI identifier oai:identifier

oai:digitalcommons.wayne.edu:oa_dissertations-1905