Significance of vocal tract geometrical variations and loudness on airflow and droplet dispersion in a two-dimensional representation of [f]

Amir A. Mofakham, Brian T. Helenbrook, Tanvir Ahmed, Byron D. Erath, Andrea R. Ferro, Deborah M. Brown, Goodarz Ahmadi

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

The significance of respiratory droplet transmission in spreading respiratory diseases such as COVID-19 has been identified by researchers. Although one cough or sneeze generates a large number of respiratory droplets, they are usually infrequent. In comparison, speaking and singing generate fewer droplets, but occur much more often, highlighting their potential as a vector for airborne transmission. However, the flow dynamics of speech and the transmission of speech droplets have not been fully investigated. To shed light on this topic, two-dimensional geometries of a vocal tract for a labiodental fricative [ f ] were generated based on real-Time MRI of a subject during pronouncing [ f ]. In these models, two different curvatures were considered for the tip tongue shape and the lower lip to highlight the effects of the articulator geometries on transmission dynamics. The commercial ANSYS-Fluent CFD software was used to solve the complex expiratory speech airflow trajectories. Simultaneously, the discrete phase model of the software was used to track submicron and large size respiratory droplets exhaled during [ f ] utterance. The simulations were performed for high, normal, and low lung pressures to explore the influence of loud, normal, and soft utterances, respectively, on the airflow dynamics. The presented results demonstrate the variability of the airflow and droplet propagation as a function of the vocal tract geometrical characteristics and loudness.

Original languageEnglish (US)
Title of host publicationFluid Mechanics; Micro and Nano Fluid Dynamics; Multiphase Flow
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Electronic)9780791885307
DOIs
StatePublished - 2021
Externally publishedYes
EventASME 2021 Fluids Engineering Division Summer Meeting, FEDSM 2021 - Virtual, Online
Duration: Aug 10 2021Aug 12 2021

Publication series

NameAmerican Society of Mechanical Engineers, Fluids Engineering Division (Publication) FEDSM
Volume3
ISSN (Print)0888-8116

Conference

ConferenceASME 2021 Fluids Engineering Division Summer Meeting, FEDSM 2021
CityVirtual, Online
Period8/10/218/12/21

ASJC Scopus subject areas

  • Mechanical Engineering

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