自由下落唾液滴在二维旋涡流中的分散
Dispersion of Free-Falling Saliva Droplets by Two-Dimensional Vortical Flows
摘要：
呼吸道唾液液滴通过室内尾流结构的分散可能会增强各种传染病的传播，因为尾流会将携带病毒的液滴传播到整个房间。因此，本研究分析了旋涡尾流结构和呼出的多组分唾液滴之间的相互作用。一个自我推进的解析描述的偶极涡被选为模型尾流，通过一个微米大小的蒸发唾液滴云。液滴的空间位置，速度，直径和温度的跟踪和耦合到他们的本地流场。首次将尾流结构的衰减纳入分析，这对于准确预测分散液滴的沉降距离是必不可少的。该模型还考虑了非挥发性唾液成分，充分捕捉液滴气溶胶转变的本质，并预测了残留气溶胶的平衡直径。我们的分析模型揭示了尾流，液滴弛豫时间，重力和运输现象之间的非直观的相互作用。我们发现，在适当的条件下，一个病毒负载的唾液滴可能会翻译的距离两个数量级大于载体流的特征尺寸。此外，与非蒸发颗粒或纯水液滴相比，考虑液滴内的非挥发性内容物可能导致根本上不同的分散和沉降行为。因此，我们认为，更复杂的蒸发模型的实施可能是至关重要的高保真度模拟渴望评估空气中呼吸道飞沫的传播。
英文摘要：
The dispersion of respiratory saliva droplets by indoor wake structures may enhance the transmission of various infectious diseases, as the wake spreads virus-laden droplets across the room. Thus, this study analyses the interaction between vortical wake structures and exhaled multi-component saliva droplets. A self-propelling analytically-described dipolar vortex is chosen as a model wake flow, passing through a cloud of micron-sized evaporating saliva droplets. The droplets' spatial location, velocity, diameter, and temperature are traced and coupled to their local flow field. For the first time, the wake structure decay is incorporated and analyzed, which is proved essential for accurately predicting the settling distances of the dispersed droplets. The model also considers the non-volatile saliva components, adequately capturing the essence of droplet-aerosol transition and predicting the equilibrium diameter of the residual aerosols. Our analytic model reveals non-intuitive interactions between wake flows, droplet relaxation time, gravity, and transport phenomena. We reveal that given the right conditions, a virus-laden saliva droplet might translate to distances two orders of magnitude larger than the carrier-flow characteristic size. Moreover, accounting for the non-volatile contents inside the droplet may lead to fundamentally different dispersion and settling behavior compared to non-evaporating particles or pure water droplets. Ergo, we suggest that the implementation of more complex evaporation models might be critical in high-fidelity simulations aspiring to assess the spread of airborne respiratory droplets.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
