Transition and Acoustic Excitation of Stenotic Pipe Flows at Different Reynolds Numbers

A human respiratory system consists of phonation components that are coupled in a complex manner in order to ensure various vital functions, in particular voice generation. The interdisciplinary nature of the processes controlling sound generation complicates the analysis. Analytical studies are limited and can only be used to characterize the main acoustic sources in connection to various types of fluid motion. Numerical investigations of sound generation require an accurate simulation of the flow field with a proper representation of the respiratory pathways and process conditions in order to get the acoustic source terms. Furthermore, voice formation is closely related to the resonance of acoustic modes in and around the mouth cavity; in order to be able to model this properly, it is essential to identify first the sound sources excited within the vocal tract.