Flow dynamics of droplets expelled during sneezing

Prateek Bahl; Charitha de Silva; C Raina MacIntyre; Shovon Bhattacharjee; Abrar Ahmad Chughtai; Con Doolan

doi:10.1063/5.0067609

Flow dynamics of droplets expelled during sneezing

Phys Fluids (1994). 2021 Nov;33(11):111901. doi: 10.1063/5.0067609. Epub 2021 Nov 2.

Authors

Prateek Bahl¹, Charitha de Silva¹, C Raina MacIntyre², Shovon Bhattacharjee², Abrar Ahmad Chughtai³, Con Doolan¹

Affiliations

¹ School of Mechanical and Manufacturing Engineering, UNSW Sydney, Kensington NSW 2052, Australia.
² Biosecurity Program, The Kirby Institute, UNSW Sydney, Kensington, NSW 2052, Australia.
³ School of Population Health, UNSW Sydney, Kensington, NSW 2052, Australia.

Abstract

Respiratory infections transmit through droplets and aerosols generated by the infected individual during respiratory emissions. It is essential to study the flow dynamics of these emissions to develop strategies for mitigating the risk of infection. In particular, the dynamics of droplets expelled during violent exhalations such as sneezing is crucial, but has received little attention to date. Here, for the first time, we present the results of droplet dynamics of 35 sneezes, obtained from four volunteers, using particle tracking velocimetry experiments. Our results reveal a mean droplet velocity of 2-5.4 m/s across the different subjects. These values are significantly lower than what is usually assumed in the studies simulating or replicating sneezes. Furthermore, the large variation in droplet speeds, flow direction, spread angle, and head movement is also quantified. These findings will enable the refinement of models and simulations of sneezes toward improving infection control guidelines.