Variability in expiratory trajectory angles during consonant production by one human subject and from a physical mouth model: Application to respiratory droplet emission
Variability in expiratory trajectory angles during consonant production by one human subject and from a physical mouth model: Application to respiratory droplet emission
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DOI：
10.1111/ina.12908
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发表时间：
2021-07-23
期刊：
影响因子：
5.8
通讯作者：
Erath, Byron D.
中科院分区：
文献类型：
--
作者：
Ahmed, Tanvir;Wendling, Hannah E.;Erath, Byron D.
COVID-19大流行凸显了需要提高对呼气排放过程中液滴传输的理解。虽然历史上的重点一直放在咳嗽和打喷嚏等暴力事件上，但对无症状和症状前传播的认识表明，需要考虑其他方式，如说话。准确预测由说话产生的感染风险需要了解所产生的液滴尺寸分布以及将液滴输送到周围环境中的呼气流场。这项工作表明，由辅音产生产生的呼气流场是高度不稳定的，表现出非常广泛的辅音间和辅音内的变化，平均喷射角从大约+30度到-30度不等。此外，实施物理口腔模型来量化[f]和[theta]的摩擦音发音的呼气流场表明，嘴唇处的流速高于先前预测的流速，达到20-30 m/s，并且所得轨迹是不稳定的。由于大小液滴的运输都直接受到气流的大小和轨迹的影响，这些研究结果表明，以前的研究在语音过程中的流动动力学在很大程度上低估了流体的渗透距离，可以实现特定的辅音发音。
The COVID-19 pandemic has highlighted the need to improve understanding of droplet transport during expiratory emissions. While historical emphasis has been placed on violent events such as coughing and sneezing, the recognition of asymptomatic and presymptomatic spread has identified the need to consider other modalities, such as speaking. Accurate prediction of infection risk produced by speaking requires knowledge of both the droplet size distributions that are produced, as well as the expiratory flow fields that transport the droplets into the surroundings. This work demonstrates that the expiratory flow field produced by consonant productions is highly unsteady, exhibiting extremely broad inter- and intra-consonant variability, with mean ejection angles varying from approximate to+30 degrees to -30 degrees. Furthermore, implementation of a physical mouth model to quantify the expiratory flow fields for fricative pronunciation of [f] and [theta] demonstrates that flow velocities at the lips are higher than previously predicted, reaching 20-30 m/s, and that the resultant trajectories are unstable. Because both large and small droplet transport are directly influenced by the magnitude and trajectory of the expirated air stream, these findings indicate that prior investigations of the flow dynamics during speech have largely underestimated the fluid penetration distances that can be achieved for particular consonant utterances.