TY - GEN
T1 - Significance of vocal tract geometrical variations and loudness on airflow and droplet dispersion in a two-dimensional representation of [f]
AU - Mofakham, Amir A.
AU - Helenbrook, Brian T.
AU - Ahmed, Tanvir
AU - Erath, Byron D.
AU - Ferro, Andrea R.
AU - Brown, Deborah M.
AU - Ahmadi, Goodarz
N1 - Funding Information:
This work was supported by the National Science Foundation under grant number CBET:2029548.
Publisher Copyright:
© 2021 American Society of Mechanical Engineers (ASME). All rights reserved.
PY - 2021
Y1 - 2021
N2 - 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.
AB - 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.
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U2 - 10.1115/FEDSM2021-65485
DO - 10.1115/FEDSM2021-65485
M3 - Conference contribution
AN - SCOPUS:85116602781
T3 - American Society of Mechanical Engineers, Fluids Engineering Division (Publication) FEDSM
BT - Fluid Mechanics; Micro and Nano Fluid Dynamics; Multiphase Flow
PB - American Society of Mechanical Engineers (ASME)
T2 - ASME 2021 Fluids Engineering Division Summer Meeting, FEDSM 2021
Y2 - 10 August 2021 through 12 August 2021
ER -