Degree Type

Thesis

Date of Award

2017

Degree Name

Master of Science

Department

Aerospace Engineering

Major

Aerospace Engineering

First Advisor

Dr. Anupam Sharma

Abstract

Title: Techniques to identify physical sources of aerodynamically generated sound

Presenter: Vishal T Vijay

Abstract:

Aerodynamic noise is a problem that has been haunting researchers for decades. As the

proximity of society to aerodynamic machinery increases, it becomes even more imperative that

methods to reduce aerodynamic noise are developed. In an attempt to better understand the

mechanism of aerodynamic sound generation, a method is developed to isolate the sources of

sound from its effects.

The approach is to design a filter designed using the dispersion relation to remove the

propagation effects from the flow. The dispersion relation is well defined in the frequency-wavenumber

domain and hence the flow parameter, pressure, is transformed through successive

Fourier transforms in time and space into this domain. The method was verified on analytical

solutions of single-frequency point sources, monopole, dipole, and quadrupole. The approach

was then applied to CFD solutions of these point sources obtained using the flow solver FDL3DI.

The results are promising in that the filtering algorithm removes the propagation effects of

the sound sources. Although much lesser in magnitude, some noise inevitably remains after the

filtering procedure due to several limitations including finiteness of data, sampling frequency,

etc. Different approaches were considered to implement the filtering algorithm to mitigate the

errors with varying degree of success.

DOI

https://doi.org/10.31274/etd-180810-6110

Copyright Owner

Vishal T Vijay

Language

en

File Format

application/pdf

File Size

74 pages

Share

COinS