E3S Web Conf.
Volume 356, 2022The 16th ROOMVENT Conference (ROOMVENT 2022)
|Number of page(s)||4|
|Section||Airflow Visualization, Measurement and Simulation|
|Published online||31 August 2022|
Numerical investigation of the effects of environmental conditions, droplet size, and social distance on interpersonal droplet transmission in a deep urban street canyon
1 Sciences, Sun Yat-sen University, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
2 Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-sen University, Zhuhai, PR China.
3 Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
Corresponding author: email@example.com
This study investigated the interpersonal droplet transmission between a healthy and an infected person in a deep and narrow street canyon using Computational Fluid Dynamics (CFD) simulation. The CFD simulations modelled various droplet sizes (Dp), background wind speeds (Uref), relative humidity (RH), and social distances (D) to estimate their effects on interpersonal droplet transmission. The results revealed noticeably opposite effects of these factors. For example, small background wind moved droplets upward and suspended them in the air for a longer time while high wind speeds distributed droplets in the street canyon with few of them retained in the air. Relative humidity had a trifling impact on dispersing small droplets (10μm, 25μm, 50μm), whereas it significantly modified the dispersion of large droplets, especially in small background wind speeds. Furthermore, small droplets travelled longer distances in dry air and were either deposited on the surrounding buildings’ walls or suspended in the air. In contrast, larger droplets in moist air rapidly deposited on the ground or the infected person’s body. In dry air, 45% of large droplets were inhaled or suspended in the air, exposing pedestrians to contaminated droplets. Large social distances significantly diluted the small droplets but increased the infection risk from large droplets because of the complex interaction of the ambient airflow and the gravity. It is recommended to keep social distances of 2 m and 4 m for pedestrians in deep urban street canyons in Windy condition and Calm-Wet condition, respectively.
© The Authors, published by EDP Sciences, 2022
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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