PhD DEFENSE BY ANNE BOUVET

On the 29th of December 2019, Anne Bouvet will defend her PhD entitled "Experimental and theoretical contribution to the analysis and the modelling of the vocal folds vibration"

 

This PhD project was supervised by Xavier Pellorson and Annemie Van Hirtum (LEGI) and carried out in collaboration with the GIPSA Lab.

 

The defense will take place at 9 am in the conference room of the LEGI (K118).


SUMMARY

 

The production of the human voice is generated by vocal folds auto-oscillation, due to the interaction between the air flow coming from the lungs and the elastic structure of the vocal folds. The purpose of this thesis is to realise an experimental and theoretical study in order to improve the understanding and modelling of this phenomenon and some of its perturbations.

Firstly, the MSePGG algorithm is proposed for the calibration of a non-invasive device for in vivo glottal area measurements. The algorithm is validated on mechanical replicas and illustrated for measurements on a human speaker.

Secondly, the vocal folds are covered by a thin layer of liquid, essential for phonation. An experimental approach is proposed to systematically study the influence of the presence of liquid on vocal fold replicas. Water spraying is shown to alter basic voice parameters as well as their perturbation. A simplified theoretical flow model accounting for the presence of both air and water is proposed and validated.

Thirdly, the effect of vertical vocal fold angular asymmetry, as occurring in the case of unilateral vocal fold paralysis, on the fluid-structure interaction is experimentally assessed. It is found that loss of full vocal folds contact leads to important variation on phonation features and their variations.

A simple theoretical model is shown to fit the increase of auto-oscillation onset threshold pressure with asymmetry angle. For future clinical applications obtained results suggest the further development of the MSePGG device and illustrate the multiple potential causes of voice perturbation.