On coughing and airborne droplet transmission to humans
On coughing and airborne droplet transmission to humans
复制标题
DOI：
10.1063/5.0011960
复制
发表时间：
2020-05-01
影响因子：
4.6
通讯作者：
Drikakis, Dimitris
中科院分区：
文献类型：
--
作者：
Dbouk, Talib;Drikakis, Dimitris
我们对病毒的空气传播机制的理解是不完整的。本文采用计算多相流体动力学和传热来研究人类咳嗽引起的唾液颗粒的传输、分散和蒸发。唾液滴在空气中的喷射过程被应用于模拟人类咳嗽的真实事件。我们采用了一种基于完全耦合欧拉-拉格朗日技术的先进三维模型，该模型考虑了相对湿度、湍流色散力、液滴相变、蒸发和破裂，以及液滴-液滴和液滴-空气的相互作用。我们计算研究风速对社交距离的影响。对于在20摄氏度和50%相对湿度的空气中轻度咳嗽的人来说，我们发现，根据风速，携带人类唾液疾病的飞沫可能会传播到意想不到的相当远的距离。当风速接近于零时，唾液液滴没有移动2米，这在社会距离建议范围内。然而，在4 ~ 15 km/h的风速范围内，我们发现唾液液滴的移动距离可达6 m，而在风向上，唾液液滴的浓度和液滴大小都有所下降。我们的研究结果表明，考虑到环境条件，2米的社会距离可能是不够的。需要进一步的研究来量化诸如环境相对湿度和温度等参数的影响。
Our understanding of the mechanisms of airborne transmission of viruses is incomplete. This paper employs computational multiphase fluid dynamics and heat transfer to investigate transport, dispersion, and evaporation of saliva particles arising from a human cough. An ejection process of saliva droplets in air was applied to mimic the real event of a human cough. We employ an advanced three-dimensional model based on fully coupled Eulerian-Lagrangian techniques that take into account the relative humidity, turbulent dispersion forces, droplet phase-change, evaporation, and breakup in addition to the droplet-droplet and droplet-air interactions. We computationally investigate the effect of wind speed on social distancing. For a mild human cough in air at 20 degrees C and 50% relative humidity, we found that human saliva-disease-carrier droplets may travel up to unexpected considerable distances depending on the wind speed. When the wind speed was approximately zero, the saliva droplets did not travel 2 m, which is within the social distancing recommendations. However, at wind speeds varying from 4 km/h to 15 km/h, we found that the saliva droplets can travel up to 6 m with a decrease in the concentration and liquid droplet size in the wind direction. Our findings imply that considering the environmental conditions, the 2 m social distance may not be sufficient. Further research is required to quantify the influence of parameters such as the environment's relative humidity and temperature among others.