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Effect of sneezing on the flow around a face shield

A flow analysis around a face shield was performed to examine the risk of virus infection when a medical worker wearing a face shield is exposed to a patient’s sneeze from the front. We ensured a space between the shield surface and the face of the human model to imitate the most popularly used face...

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Autores principales: Akagi, Fujio, Haraga, Isao, Inage, Shin-ichi, Akiyoshi, Kozaburo
Formato: Online Artículo Texto
Lenguaje:English
Publicado: AIP Publishing LLC 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7757660/
https://www.ncbi.nlm.nih.gov/pubmed/33362403
http://dx.doi.org/10.1063/5.0031150
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author Akagi, Fujio
Haraga, Isao
Inage, Shin-ichi
Akiyoshi, Kozaburo
author_facet Akagi, Fujio
Haraga, Isao
Inage, Shin-ichi
Akiyoshi, Kozaburo
author_sort Akagi, Fujio
collection PubMed
description A flow analysis around a face shield was performed to examine the risk of virus infection when a medical worker wearing a face shield is exposed to a patient’s sneeze from the front. We ensured a space between the shield surface and the face of the human model to imitate the most popularly used face shields. In the present simulation, a large eddy simulation was conducted to simulate the vortex structure generated by the sneezing flow near the face shield. It was confirmed that the airflow in the space between the face shield and the face was observed to vary with human respiration. The high-velocity flow created by sneezing or coughing generates vortex ring structures, which gradually become unstable and deform in three dimensions. Vortex rings reach the top and bottom edges of the shield and form a high-velocity entrainment flow. It is suggested that vortex rings capture small-sized particles, i.e., sneezing droplets and aerosols, and transport them to the top and bottom edges of the face shield because vortex rings have the ability to transport microparticles. It was also confirmed that some particles (in this simulation, 4.4% of the released droplets) entered the inside of the face shield and reached the vicinity of the nose. This indicates that a medical worker wearing a face shield may inhale the transported droplets or aerosol if the time when the vortex rings reach the face shield is synchronized with the inhalation period of breathing.
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spelling pubmed-77576602020-12-23 Effect of sneezing on the flow around a face shield Akagi, Fujio Haraga, Isao Inage, Shin-ichi Akiyoshi, Kozaburo Phys Fluids (1994) Articles A flow analysis around a face shield was performed to examine the risk of virus infection when a medical worker wearing a face shield is exposed to a patient’s sneeze from the front. We ensured a space between the shield surface and the face of the human model to imitate the most popularly used face shields. In the present simulation, a large eddy simulation was conducted to simulate the vortex structure generated by the sneezing flow near the face shield. It was confirmed that the airflow in the space between the face shield and the face was observed to vary with human respiration. The high-velocity flow created by sneezing or coughing generates vortex ring structures, which gradually become unstable and deform in three dimensions. Vortex rings reach the top and bottom edges of the shield and form a high-velocity entrainment flow. It is suggested that vortex rings capture small-sized particles, i.e., sneezing droplets and aerosols, and transport them to the top and bottom edges of the face shield because vortex rings have the ability to transport microparticles. It was also confirmed that some particles (in this simulation, 4.4% of the released droplets) entered the inside of the face shield and reached the vicinity of the nose. This indicates that a medical worker wearing a face shield may inhale the transported droplets or aerosol if the time when the vortex rings reach the face shield is synchronized with the inhalation period of breathing. AIP Publishing LLC 2020-12-01 2020-12-08 /pmc/articles/PMC7757660/ /pubmed/33362403 http://dx.doi.org/10.1063/5.0031150 Text en © 2020 Author(s) Published under license by AIP Publishing. 1070-6631/2020/32(12)/127105/8/$30.00 All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Articles
Akagi, Fujio
Haraga, Isao
Inage, Shin-ichi
Akiyoshi, Kozaburo
Effect of sneezing on the flow around a face shield
title Effect of sneezing on the flow around a face shield
title_full Effect of sneezing on the flow around a face shield
title_fullStr Effect of sneezing on the flow around a face shield
title_full_unstemmed Effect of sneezing on the flow around a face shield
title_short Effect of sneezing on the flow around a face shield
title_sort effect of sneezing on the flow around a face shield
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7757660/
https://www.ncbi.nlm.nih.gov/pubmed/33362403
http://dx.doi.org/10.1063/5.0031150
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