Violent respiratory diseases, i.e., coronavirus (COVID-19), spread through saliva in coughs and sneezes or are even exhaled in the form of microbial pathogen micro-droplets. Therefore, in this work, a comprehensive fully coupled Eulerian–Lagrangian method has been applied for infection control, thus leading to a deeper understanding of the saliva-disease-carrier droplet transmission mechanisms and also of their trajectory tracking by using the OpenFOAM package. This model determines the droplet–air interactions, the breakup process, and turbulent dispersion forces on each micro-droplet that is expelled within the respiratory tract in a correct way. By examining a broad range of initial velocities, size distributions, injection angles of saliva micro-droplets, and mouth opening areas, we predict the maximum opening area that can be driven by micro-droplets. One important contribution of this work is to present a correlation for the length and width of the overall direct maximum reach of the micro-droplets, driven by a wide range of mild coughs to intense sneezes. Our results indicate that the movement of the expelled droplets is mainly influenced by their size, angle, velocity, and environmental factors. During a virus crisis, like COVID-19, this paper can be used to determine the “social distance” between individuals to avoid contamination, by inhaling or touching their bodies, due to these saliva-disease-carrier droplets in sneezing, at various social distance positions such as face-to-face, meeting standing, and near equipment. The safe distance must be increased to around 4 m during a sneeze. By wearing a face mask and by bending the head during a sneeze as a protective action, we can reduce the contamination area to one-third and three-quarters, respectively. Furthermore, the dispersion of the film of the expelled saliva micro-droplets and the spatial relationship between the subjects, which affects the airflow inside the room, are also analyzed in detail.

中文翻译：

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打喷嚏和咳嗽期间携带病毒的唾液飞沫分布的数值模型


严重的呼吸道疾病，即冠状病毒（COVID-19），通过咳嗽和打喷嚏时的唾液传播，甚至以微生物病原体微滴的形式呼出。因此，在这项工作中，采用全面的全耦合欧拉-拉格朗日方法进行感染控制，从而更深入地了解唾液疾病携带者飞沫传播机制以及使用 OpenFOAM 软件包对其轨迹跟踪。该模型确定了液滴与空气的相互作用、破碎过程以及以正确方式在呼吸道内排出的每个微液滴的湍流分散力。通过检查各种初始速度、尺寸分布、唾液微滴的喷射角度和张口面积，我们预测了微滴可以驱动的最大开口面积。这项工作的一个重要贡献是提出了由各种轻微咳嗽到剧烈喷嚏驱动的微液滴总体直接最大到达范围的长度和宽度的相关性。我们的结果表明，排出液滴的运动主要受其尺寸、角度、速度和环境因素的影响。在像 COVID-19 这样的病毒危机期间，本文可用于确定个体之间的“社交距离”，以避免通过吸入或触摸自己的身体而受到污染，因为这些唾液疾病携带者在打喷嚏时、在各种社交活动中都会产生飞沫。距离位置，例如面对面、会议站立和靠近设备。打喷嚏时必须将安全距离增加至 4 m 左右。通过戴口罩和打喷嚏时低下头作为保护措施，我们可以分别将污染面积减少到三分之一和四分之三。 此外，还详细分析了排出的唾液微滴薄膜的分散情况以及影响房间内气流的受试者之间的空间关系。