Numerical investigation of respiratory drops dynamics released during vocalization

Release of drops from a human body has been the focus of many recent investigations due to the current COVID-19 pandemic. Indirect virus transmission from asymptomatic individuals has been proved to be an important infectious route with great complexity for being quantified, detected and mitigated. We show in this work a detailed and novel numerical investigation of drops released during vocalization from a thermal manikin using a large eddy simulation (LES) coupled with Lagrangian tracking of drops. The vocalization experiment was modelled using existing data from the literature for modelling exhaled airflow, emission rate and size distribution. A special focus was taken on the definition of the boundary conditions for the exhalation process. Turbulence was compared with experimental data for the near mouth region for 75 exhalation breathing cycles, and showed the sensitivity of different modelling assumptions at the mouth inlet. The results provide insights of special interest for validating other simplified models, operating existing ventilation systems or designing new ones..