Date of Award
Master of Science
Dr. Anupam Sharma
Title: Techniques to identify physical sources of aerodynamically generated sound
Presenter: Vishal T Vijay
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.
Vishal T Vijay
Vijay, Vishal T., "Techniques to identify physical sources of aerodynamically generated sound" (2017). Graduate Theses and Dissertations. 16480.