Real-Time Sound Synthesis of Aeroacoustic Sounds using Physically Derived Models

Abstract

This thesis examines the use of a novel synthesis approach to reproduce aeroacoustic sound effects. This requires research into the fi eld of fluid dynamics to understand the principles which lead to a number of fundamental aeroacoustic tones. Previous research has shown that these fundamental tones can be represented by compact sound sources. Three compact sound source synthesis models are developed representing three different fundamental aeroacoustic tones, the Aeolian tone, the cavity tone and the edge tone. A number of semi-empirical equations, ones where simpli cations, generalisations or observations are considered, are found which provide mathematical relationships between the defi ning fluid dynamic parameters. Often these equations have been developed prior to computers being able to solve the complex uid dynamic equations. Frequently, these equations were developed to assist scientists and engineers reduce the aeroacoustic noise. In this instance, the equations are used to replicate the aeroacoustic sounds. The methodology of developing a compact sound source synthesis model for each of the aeroacoustic tones is presented and how this relates to the chosen noise shaping synthesis technique. Objective evaluation shows the semi-physical synthesis models perform well when compares to previously published results. Following the development of the compact sound source synthesis models, three sound e ect models are developed. These provide examples of how the synthesis models can be used to provide procedural audio sound e ects. These are swinging objects, like a sword of a club; a propeller; an Aeolian harp. Evaluation of these are carried out, with subjective evaluation indicating equal or better performance than an alternative synthesis method. The uniqueness of the implementations presented from this research is that combines the low computational requirements of a signal-based model while the parameterisation draws from equations obtained from aeroacoustic research.