A note on the stability characteristics of the respiratory events

The present outbreak enables the researchers from fluid mechanics to widen the understanding of expelling respiratory liquids from a unique perspective to diminish the persistence of COVID-19. This article focuses on uncovering the instability mechanism responsible for forming droplets and aerosols during respiratory events such as breathing, talking, coughing and sneezing. We illustrate a mathematical framework by revisiting the model (Vadivukkarasan and Panchagnula, 2017) and show the associated instabilities during respiratory events. We envisage the combined Rayleigh-Taylor-Kelvin-Helmholtz (R-T-K-H) model as a robust tool for respiratory events. This study highlights the distinct possibility of respiratory droplet formation over multiple instabilities and provides a fundamental understanding. We present the different dominant modes through a ternary phase diagram for three-dimensional numbers (Bond number and Weber numbers). Furthermore, this model can be extended phenomenologically to viscous fluids to satisfy mucus and saliva in the respiratory liquids. (C) 2021 Elsevier Masson SAS. All rights reserved.

Automated summary

This study analyzes the instability mechanism responsible for forming droplets and aerosols during respiratory events, proposing a mathematical framework and suggesting the Rayleigh-Taylor-Kelvin-Helmholtz model as a powerful tool. It highlights the possibility of respiratory droplet formation over multiple instabilities and provides a fundamental understanding.