Two-Dimensional evaporation dynamics of a respiratory droplet in context of COVID-19

Respiratory droplets are considered the primary mode of transmission of COVID-19. The droplets ejected through the exhalation process during cough, sneeze, speech consist of a complex mixture of volatile and non-volatile substances. While transmitted and translated in air with perturbations, these complex liquid droplets undergo a series of coupled thermo-physical processes. Contemplating an individual airborne droplet in a cloud of infectious droplets interacting with air vortices, boundary layers and wakes develop on account of relative motion between the droplet and the ambient air. The mathematical description of the coupled subprocesses, including droplet aerodynamics, heat, and mass transfer, which controls the evaporation dynamics, were solved to obtain the solution. The two-dimensional model gives a complete analysis encompassing the gas phase coupled with the liquid phase responsible for the airborne droplet kinetics' complex evaporation phenomenon in the ambient environment. The transient inhomogeneity of temperature and concentration gradient in the liquid phase of the respiratory droplet caused due to the convective and diffusive transports are captured in the 2D model.