A Computational Model of Phonation-Induced Aerosolization

COREY LYNN MURPHEY, Allison Hilger, Elizabeth Bradley, University of Colorado - Boulder

     Abstract Number: 199
     Working Group: Aerosol Science of Infectious Diseases: Lessons and Open Questions on Models, Transmission and Mitigation

Abstract
Human phonation induces the formation and ejection of aerosols from the mouth. In infectious speakers, phonation-induced aerosolization can facilitate the transmission of airborne viruses. However, the formation of such aerosols is challenging to visualize experimentally due to the complex structure of the larynx, the inability to directly measure aerosol generation at the laryngeal level, and the length scale at which fluid atomization occurs. Further, an experimental aerosol formation study employs an aerosol particle sizer (APS) that only measures exhaled aerosols, which have been filtered within the intermediate vocal tract between the larynx and the mouth. To understand the mechanisms involved in laryngeal speech-induced aerosol formation, we have developed a computational framework that models the ejection and subsequent breakup of sessile liquid on the surface of the vocal folds. A vibration-induced Faraday instability drives the emission of droplets from the fluid-lined mucosal layer of the vocal folds. We apply Tate's law to simulate the resulting droplet ejection. This vibration-induced atomization model accounts for nonlinear vibrational elastodynamics and fluid-structure interaction between exhaled air and the vocal fold tissues. The output of this model yields a spray distribution that we compare to experimental aerosol size distributions collected during phonation tasks.