Date of Award

12-2022

Document Type

Thesis

Degree Name

Master of Science in Aeronautical Engineering

Department

Department of Aeronautics and Astronautics

First Advisor

Frederick R. Schauer, PhD

Abstract

This research focused on potential design optimizations for small propellers. Designs sought to reduce noise generated without sacrificing efficiency by “unloading” the propeller tip by reducing angle of attack near the tip. To see if nearfield performance improvements translated to a reduction in farfield sound pressure level, farfield experimental acoustic testing was performed on propellers that had been measured experimentally in the nearfield. The farfield results provided limited insight due to an equipment malfunction during testing. However, a large data set was obtained, which provides opportunities for future analyses. A computational simulation sought to recreate some of the nearfield experiments to see whether acoustics could be predicted computationally. The computational results showed that the solver struggled to match the experimental results at locations with a high pressure gradient but performed better where the pressure gradient was lower. Results were sensitive to time step, especially further from the propeller, which was believed to be due to the propeller “jolting” through the flow when the time step was too large.

AFIT Designator

AFIT-ENY-MS-22-D-057

Comments

A 12-month embargo was observed for posting this thesis on AFIT Scholar.

Approved for public release. PA case number on file.

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