Prediction on Transmission Flow Path of Human Coughs into Airborne

Abstract

Coronavirus disease 2019 has become a global pandemic that causes illnesses ranging from normal fever to more severe diseases to be hospitalized or die. Understanding the mechanisms of the droplet’s transmission is incomplete. This project adopts the computational fluid dynamics (CFD) method to investigate the dispersion and the transport velocities after people are coughed into the air with and without the facemask. This project has employed 2 types of simplified three-dimensional models covering with and without a facemask. An ejection process of the saliva droplets from the mouth was to mimic the real human cough into the air. The size of the saliva droplets defines as 50-70 µm in diameter, inferring the size range which may potentially be more infectious. Besides, consider the effect of the droplet’s flow velocities which were 6 m/s, 14 m/s, and 22 m/s that cause the motion of the droplets in a confined room condition. The relationship between the saliva droplet flow characteristics and the dispersion of the droplet’s particle velocities deposited on the areas was investigated. Hence, the results show that the higher the velocity, the higher the dispersion rate. However, for the people who wear a facemask, it provides great protection and decelerates the outspread rates. Further research is required to take into account other factors such as the environmental relative humidity, ventilation, and indoor versus outdoor.