Fluid Dynamics of Speech and the Spatial-Temporal Distribution of Aerosols

语音流体动力学和气溶胶的时空分布

• 批准号: 2116184
• 负责人: Howard Stone
• 金额: $ 35.26万
• 依托单位: Princeton University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2116184&HistoricalAwards=false
• 关键词: Fluid; Dynamics; Speech; Spatial; Temporal

The spread of COVID-19 highlights the lack of guidelines and mitigation strategies for reducing the impact of a contagious virus in the absence of a vaccine. In fact, casual interactions, such as speaking, involving asymptomatic individuals are believed to play a significant role in virus transmission. Nevertheless, there are few quantitative studies of the influence of the phonetic features of speech on the spatial extent of the exhaled flows, nor are the corresponding airflows between a pair of speakers known. Such studies have largely been absent from the fluid mechanics and transport phenomena literatures, and even absent more generally from quantitative studies of public health. One approach for tackling this theme of “localized transport” of pathogen at the scale of individuals is to use model experiments representative of the airflows in speech along with numerical simulations based on the corresponding equations of fluid motion to characterize the spatial and temporal features of the airflows, with attention given, by incorporating knowledge in linguistics, to the phonetic-features characteristic of spoken English. This study will fill this important gap in the literature and allow broader thinking about the fluid dynamics of pathogen transmission between people, as well as animals which are important to the food supply. It will also provide insights necessary to assess risk of infection in models of casual interactions. The outreach efforts included characterize the investigator’s approaches to engaging with, teaching, and mentoring future research scientists, including continuing an annual “holiday” lecture that has been delivered since 2002. The goal of this project is to provide new qualitative insights and quantitative characterization of the airflows typical of conversations, as it is now better appreciated that airborne transport can, in many cases, be a major, if not the dominant, mechanism of viral/pathogen transmission. In fact, the realization of dangers posed by airborne spread of COVID-19 surprised the CDC and WHO for many months despite 100 years of research in public health since the 1918 pandemic. To address this challenge the research to be performed will integrate experiments and numerical simulations in three systematic aims. First, the development of flows in speech will be quantified by measuring pressure and flow rate signals characteristic of sounds and words, including the signatures of vowels, consonants, and plosives. The physics of the flow will be investigated in experiments using particle-image velocimetry and a laser-illuminated sheet of fog droplets around a speaker and corresponding image processing, and direct numerical simulations will solve the Navier-Stokes equations with initial and boundary conditions consistent with the experiments. Then, experiments and numerical simulations will be used to study flows in face-to-face conversations, including the key role played by the vertical offset between the source flows, and the corresponding spread of exhaled material. Finally, experiments and numerical simulations will characterize the influence of a nearby horizontal boundary, such as a table, which influences horizontal propagation of exhaled material. The results will be made available to other researchers who can then also take advantage of this database. The research themes will advance the understanding of pathogen transport that may accompany fluid flows of speech that are characteristic of casual interactions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

COVID-19的传播突出表明，在没有疫苗的情况下，缺乏减少传染性病毒影响的指导方针和缓解战略。事实上，不经意的互动，例如涉及无症状个体的说话，被认为在病毒传播中起着重要作用。然而，关于语音语音特征对呼出气流空间范围的影响的定量研究很少，也不知道一对说话者之间相应的气流。在流体力学和输运现象的文献中，甚至在公共卫生的定量研究中，这种研究在很大程度上是缺失的。解决病原体在个体尺度上的“局部迁移”这一主题的一种方法是使用代表语音气流的模型实验以及基于相应流体运动方程的数值模拟来表征气流的空间和时间特征，并通过结合语言学知识来关注英语口语的语音特征。这项研究将填补这一重要的文献空白，并允许人们更广泛地思考病原体在人与人之间传播的流体动力学，以及对食物供应很重要的动物。它还将为评估偶然相互作用模型中的感染风险提供必要的见解。拓展工作包括研究人员参与、教学和指导未来研究科学家的方法，包括继续举办自2002年以来的年度“假日”讲座。该项目的目标是提供新的定性见解和定量表征典型的谈话气流，因为它现在更好地认识到，在许多情况下，空气运输可以是一个主要的，如果不是主要的，病毒/病原体传播机制。事实上，尽管自1918年大流行以来在公共卫生领域进行了100年的研究，但疾病预防控制中心和世卫组织数月来一直对COVID-19空气传播带来的危险感到惊讶。为了解决这一挑战，研究将在三个系统的目标中整合实验和数值模拟。首先，语音流的发展将通过测量声音和单词特征的压力和流量信号来量化，包括元音、辅音和爆破音的特征。流动的物理性质将在实验中进行研究，使用粒子图像测速法和激光照射的雾滴片围绕扬声器和相应的图像处理，并直接数值模拟将求解具有与实验一致的初始和边界条件的Navier-Stokes方程。然后，实验和数值模拟将用于研究面对面对话中的流动，包括源流之间的垂直偏移所起的关键作用，以及相应的呼出物质的传播。最后，实验和数值模拟将描述附近水平边界（如工作台）对呼出物质水平传播的影响。研究结果将提供给其他研究人员，他们也可以利用这个数据库。研究主题将促进对病原体运输的理解，这种运输可能伴随着言语的流体流动，这是偶然互动的特征。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Tracking the air exhaled by an opera singer

• DOI: 10.1103/physrevfluids.6.110503
• 发表时间: 2021-11-15
• 期刊: PHYSICAL REVIEW FLUIDS
• 影响因子: 2.7
• 作者: Bourrianne, Philippe;Kaneelil, Paul R.;Stone, Howard A.
• 通讯作者: Stone, Howard A.

Quantifying the effect of a mask on expiratory flows

• DOI: 10.1103/physrevfluids.6.110511
• 发表时间: 2021-11-23
• 期刊: PHYSICAL REVIEW FLUIDS
• 影响因子: 2.7
• 作者: Bourrianne, Philippe;Xue, Nan;Stone, Howard A.
• 通讯作者: Stone, Howard A.

Colliding respiratory jets as a mechanism of air exchange and pathogen transport during conversations

• DOI: 10.1017/jfm.2021.915
• 发表时间: 2021-11-16
• 期刊: JOURNAL OF FLUID MECHANICS
• 影响因子: 3.7
• 作者: Giri, Arghyanir;Biswas, Neelakash;Stone, Howard A.
• 通讯作者: Stone, Howard A.

Air Flows in Opera

歌剧院中的空气流动

• DOI: 10.1103/physrevapplied.18.024042
• 发表时间: 2022
• 期刊: Physical Review Applied
• 影响因子: 4.6
• 作者: Bourrianne, Philippe;Kaneelil, Paul R.;Abkarian, Manouk;Stone, Howard A.
• 通讯作者: Stone, Howard A.