Analysis of human cough in confined spaces: a numerical study

Abstract

The current global pandemic situation demands to gain more knowledge and understanding about viral transmission in indoor environments. Thorough knowledge of breathing, talking, coughing, singing, and sneezing of human beings in connection with infection spread is quint essential for designing mitigation measures for indoor environments. The main objective of the study is to revisit the human cough instances in an elevator setup using advanced three-dimensional adaptive mesh refinement (AMR) based computational fluid dynamics multiphase flow solver. The present work makes use of the computationally effective AMR method to resolve unsteady complex flow physics involving heat and mass transfer in a turbulent multiphase flow. The Eulerian dispersion medium is considered as a multicomponent ideal gas mixture consisting of O2, N2 and H2O and the Lagrangian dispersed phase of human cough is considered as pure liquid water. Simulations are performed to demonstrate the effectiveness of AMR based 3D simulations with varying AMR embedding scale. Evolution of different liquid phase size distributions has been studied by varying the number of liquid parcels. Finally, the effect of relative humidity is investigated for single cough instances. The results show about 35% evaporation for RH of 40% for 7.7 μg liquid injection for cough instance including a droplet travel distance for nearly 1.6m in the streamwise direction.