Influence of water spraying on an oscillating channel

The influence of surface hydration on the fluid–structure instability underlying vocal folds auto-oscillation during voiced speech sound production is an open research question. In this work the influence of homogeneous water spraying on an oscillating channel is investigated experimentally using several vocal folds replicas. Changes to glottal flow features are systematically quantified for a rigid replica with forced oscillation. Changes to auto-oscillation features are systematically quantified by analyzing the pressure measured upstream from deformable replicas. During auto-oscillation it is observed for increasing water volume that the first harmonic frequency decreases, its amplitude increases, cycle-to-cycle as well as overall fluctuations increase and the closing-opening asymmetry changes. Nevertheless, the magnitude of these effects differs between deformable replicas so that further systematic investigation is needed to quantify observations as well as to explore underlying mechanisms. Flow tendencies observed on all replicas support that water spraying affects the glottal flow rather then structural properties. This is an important finding for future modeling of the effect of water spraying on the fluid–structure interaction.