Webinar Highlight – Speech, Phonetics, and Saliva Rheology: Links to Asymptomatic Pathogen Transport

Date: 3 Feb 2021 (Wed)

Time: 9:30 am – 10:30am

Speaker: Professor Howard A. Stone

Moderator: Prof. Anderson Shum, Professor & Associate Head, Department of Mechanical Engineering, The University of Hong Kong

Speech is a potent route for viral transmission in the COVID-19 pandemic. Informed mitigation strategies are difficult to develop since no aerosolization mechanism in the oral cavity been visualized.

We document the spatio-temporal structure of the expelled air flow and detail how drops form using high-speed imaging.  Also, we show with high-speed imaging how phonation of common stop-consonants form and extend viscoelastic salivary filaments in a few milliseconds as moist lips open or when the tongue separates from the teeth, which produces centimeter-scale thin filaments, tens of microns in diameter, that break into speech droplets. We believe that this work will inform thinking about the role of ventilation, aerosol transport in disease transmission, and yield a better understanding of “aerophonetics.”

Brief bio:

Professor Howard A. Stone received his PhD from Caltech in 1988. In 1989, he joined the faculty of the (now) School of Engineering and Applied Sciences at Harvard University. In 2009, Howard moved to Princeton University where he is Donald R. Dixon ’69 and Elizabeth W. Dixon Professor in Mechanical and Aerospace Engineering

Professor Stone ‘s research interests are in fluid dynamics, especially as they arise in research and applications at the interface of engineering, chemistry, physics, and biology. He is a Fellow of the American Physical Society (APS), and is past Chair of the Division of Fluid Dynamics of the APS.