Abstract Respiratory activities such as sneezing generate pathogen laden droplets that can deposit in the respiratory tract of a susceptible host to initiate infection. The extent of spread of these droplets determines the safe distance between a patient and health care worker. Here, we have presented a method to visualize the droplets expelled by a sneeze using light-sheet illumination. This method of visualization provides images that clearly resolve the velocities of droplets with minimal overlapping trajectories, towards understanding their flow dynamics. Furthermore, we present the image processing techniques required to perform accurate Particle Tracking Velocimetry to understand the motion of expelled droplets. Flow fields are presented from applying this methodology over multiple sneezes which reveal that less than 1% of droplets expelled travel at velocities greater than 10 m/s and almost 80% of droplets travel at velocities less than 5 m/s. Furthermore, we observe that some droplets are generated by ligament breakup outside the mouth and some are generated within the respiratory tract. Graphic abstract

中文翻译：

---

一个捕捉喷嚏喷出液滴流动动力学的实验框架

摘要 打喷嚏等呼吸活动会产生载有病原体的飞沫，这些飞沫可以沉积在易感宿主的呼吸道中以引发感染。这些飞沫的传播程度决定了患者和医护人员之间的安全距离。在这里，我们提出了一种使用光片照明可视化喷嚏喷出的液滴的方法。这种可视化方法提供的图像清楚地解决了具有最小重叠轨迹的液滴速度，以了解它们的流动动力学。此外，我们还介绍了执行精确粒子跟踪测速以了解排出液滴的运动所需的图像处理技术。流场是通过在多次打喷嚏上应用这种方法来呈现的，这表明只有不到 1% 的液滴以大于 10 m/s 的速度排出，几乎 80% 的液滴以低于 5 m/s 的速度移动。此外，我们观察到一些飞沫是由口腔外的韧带断裂产生的，一些飞沫是在呼吸道内产生的。图形摘要