How Talking Produces Saliva Droplets: Droplet Size and Distance in Speech
Session Number
3
Advisor(s)
Jie Feng, University of Illinois Urbana-Champaign
Location
A115
Discipline
Physical Science
Start Date
15-4-2026 2:15 PM
End Date
15-4-2026 3:00 PM
Abstract
When a person talks, saliva is ejected from their mouth as all droplets. These droplets form due to the separation of saliva filaments, which stretch and break apart during speech. After the saliva is ejected, it travels as a multiphase gas cloud composed of air and suspended liquid droplets. Understanding the corresponding fluid dynamics and transport is important because it can lead to a higher understanding of pathogen transmission through speech. Previous studies have shown that the radius of the multiphase cloud produced during speech increases proportionally with the distance it travels. However, the relationship between travel distance and the size of ejected droplets remains less well understood. In this project, we investigated how the size distribution of ejected droplets relates to the distance they travel during speech. Within visible droplets, it was observed that with many words, there is a proportional dependence between travel distance and visible droplet size. These results demonstrate that many findings about the multiphase cloud may apply to visible droplets as well, and vice versa. With this knowledge, observations about visible droplets can be used to predict more accurate models such as the multiphase gas cloud.
How Talking Produces Saliva Droplets: Droplet Size and Distance in Speech
A115
When a person talks, saliva is ejected from their mouth as all droplets. These droplets form due to the separation of saliva filaments, which stretch and break apart during speech. After the saliva is ejected, it travels as a multiphase gas cloud composed of air and suspended liquid droplets. Understanding the corresponding fluid dynamics and transport is important because it can lead to a higher understanding of pathogen transmission through speech. Previous studies have shown that the radius of the multiphase cloud produced during speech increases proportionally with the distance it travels. However, the relationship between travel distance and the size of ejected droplets remains less well understood. In this project, we investigated how the size distribution of ejected droplets relates to the distance they travel during speech. Within visible droplets, it was observed that with many words, there is a proportional dependence between travel distance and visible droplet size. These results demonstrate that many findings about the multiphase cloud may apply to visible droplets as well, and vice versa. With this knowledge, observations about visible droplets can be used to predict more accurate models such as the multiphase gas cloud.