Study of the airflow through in-vitro oscillating pathological vocal folds

and introduction We present in this study experimental and theoretical results concerning the behaviour of the airflow through the glottis during phonation. This work follows our previous study on the behaviour of the flow in asymmetric models of vocal folds modelling pathologies ([6]). For sake of better control of the parameters, the vocal folds models were rigid but supplied with oscillating airflow. The measurements are now carried out on a more realistic set-up that reproduces the selfsustained oscillations of the vocal folds. It is inspired by previous works on brass player lips oscillations ([2]). By modifying asymmetricaly the mechanical properties of the vocal folds models we can simulate pathologies. We then try to reproduce the measured phenomena by use of numerical simulation with a two-mass model inspired by Lous et all. ([3]). In the first section, we describe the experimental set-up we use in this study, then we look at measurements with a special care to ‘pathological’ cases. Finally, after a brief description of the numerical model, we present numerical simulations that fit our experimental data. 1. Experimental set-up As proposed by Gilbert et all.([2]), the vocal folds are modelled by two rubber tubes of thickness 0.2 mm filled with pressurised water and mounted on cylindrical brass holders of diameter 11 mm in which half of the metal has been removed over a length Lg = 30 mm (see figure 1). The mechanical model is thus 3 times larger than in ‘real life’. The water pressure in each vocal fold i is imposed by a water column of variable height