Experimental Validation of Simplified Free Jet Turbulence Models Applied to the Vocal Tract

TL;DR

This study experimentally validates simplified turbulence models for free jets, aiming to improve understanding of turbulent sound production in speech by analyzing how vocal tract shape influences velocity distribution.

Contribution

It introduces an experimental validation of simplified turbulence models applied to vocal tract simulations, linking flow dynamics to speech sound production.

Findings

Simplified models reasonably predict velocity distribution in free jets.

Vocal tract shape parameters significantly influence turbulence characteristics.

Results support future integration of turbulence models into speech production modeling.

Abstract

Sound production due to turbulence is widely shown to be an important phenomenon involved in a.o. fricatives, singing, whispering and speech pathologies. In spite of its relevance turbulent flow is not considered in classical physical speech production models mostly dealing with voiced sound production. The current study presents preliminary results of an experimental validation of simplified turbulence models in order to estimate the time-mean velocity distribution in a free jet downstream of a tube outlet. Aiming a future application in speech production the influence of typical vocal tract shape parameters on the velocity distribution is experimentally and theoretically explored: the tube shape, length and the degree and geometry of the constriction. Simplified theoretical predictions are obtained by applying similarity solutions of the bidimensional boundary layer theory to a plane and circular free jet in still air. The orifice velocity and shape are the main model input quantities. Results are discussed with respect to the upper airways and human sound production.