Understanding Phonetic Variations in Expiratory Turbulent Puffs through 3D Particle Tracking Velocimetry

We use high-speed 3D particle tracking velocimetry (PTV) to measure turbulent puffs created by articulating various explosive consonants: p, t, and k at a distance of one meter from the subject's mouth along the puff's streamwise direction. The energy dissipation rate (ε) was calculated via five methodologies: the second-order structure function, energy spectrum, Samgorinsky method, filter space technique, and dimensional analysis. Our results indicate a clear correlation between the ε estimated by different methods and the articulated consonants. Specifically, the average ε for p and k were consistently smaller than the ε for t. This disparity may be attributable to the unique articulatory movements associated with t, such as airflow obstruction by the tongue. In addition, we reveal that different pronunciations occupy distinct regimes of feature space spanned by the mean and turbulent characteristics, suggesting that phonetic complexities can generate puffs with distinct mean and turbulent characteristics. Thus, studies of airborne disease transmission among individuals should consider phonetic complexities.