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Investigation of theoretical scaling laws using large eddy simulations for airborne spreading of viral contagion from sneezing and coughing

Using a set of large eddy point-particle simulations, we explore the fluid dynamics of an ejected puff resulting from a cough/sneeze. The ejection contains over 61 000 potentially virus-laden droplets at an injection Reynolds number of about 46 000, comparable to an actual cough/sneeze. We observe t...

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Autores principales: Liu, K., Allahyari, M., Salinas, J., Zgheib, N., Balachandar, S.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: AIP Publishing LLC 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8320469/
https://www.ncbi.nlm.nih.gov/pubmed/34335006
http://dx.doi.org/10.1063/5.0054651
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author Liu, K.
Allahyari, M.
Salinas, J.
Zgheib, N.
Balachandar, S.
author_facet Liu, K.
Allahyari, M.
Salinas, J.
Zgheib, N.
Balachandar, S.
author_sort Liu, K.
collection PubMed
description Using a set of large eddy point-particle simulations, we explore the fluid dynamics of an ejected puff resulting from a cough/sneeze. The ejection contains over 61 000 potentially virus-laden droplets at an injection Reynolds number of about 46 000, comparable to an actual cough/sneeze. We observe that global puff properties, such as centroid, puff volume, momentum, and buoyancy vary little across realizations. Other properties, such as maximum extent, shape, and edge velocity of the puff, may exhibit substantial variation. In many realizations, a portion of the puff splits off and advances along a random direction, while keeping airborne droplet nuclei afloat. This peeled-off portion provides a mechanism for virus-laden droplets to travel over large distances in a short amount of time. We also observe that the vast majority of droplets remain suspended within the puff after all liquid has evaporated. The main objectives of the study are to (i) evaluate assumptions of Balachandar's et al. theory [Int. J. Multiphase Flow 132, 103439 (2020)], which include buoyancy effects, shape of the puff, and droplet evaporation rate, (ii) obtain values of closure parameters, which include location and time of the virtual origin, and puff entrainment and drag coefficients, and (iii) evaluate the accuracy of the theory in predicting the shape, size, and location of the puff, as well as droplet number density long after ejection. The theory adequately predicts global puff properties including size, velocity, and distance traveled, the largest size of droplets that exit the puff due to settling, and the droplet size distribution within the puff long after ejection.
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spelling pubmed-83204692021-07-29 Investigation of theoretical scaling laws using large eddy simulations for airborne spreading of viral contagion from sneezing and coughing Liu, K. Allahyari, M. Salinas, J. Zgheib, N. Balachandar, S. Phys Fluids (1994) ARTICLES Using a set of large eddy point-particle simulations, we explore the fluid dynamics of an ejected puff resulting from a cough/sneeze. The ejection contains over 61 000 potentially virus-laden droplets at an injection Reynolds number of about 46 000, comparable to an actual cough/sneeze. We observe that global puff properties, such as centroid, puff volume, momentum, and buoyancy vary little across realizations. Other properties, such as maximum extent, shape, and edge velocity of the puff, may exhibit substantial variation. In many realizations, a portion of the puff splits off and advances along a random direction, while keeping airborne droplet nuclei afloat. This peeled-off portion provides a mechanism for virus-laden droplets to travel over large distances in a short amount of time. We also observe that the vast majority of droplets remain suspended within the puff after all liquid has evaporated. The main objectives of the study are to (i) evaluate assumptions of Balachandar's et al. theory [Int. J. Multiphase Flow 132, 103439 (2020)], which include buoyancy effects, shape of the puff, and droplet evaporation rate, (ii) obtain values of closure parameters, which include location and time of the virtual origin, and puff entrainment and drag coefficients, and (iii) evaluate the accuracy of the theory in predicting the shape, size, and location of the puff, as well as droplet number density long after ejection. The theory adequately predicts global puff properties including size, velocity, and distance traveled, the largest size of droplets that exit the puff due to settling, and the droplet size distribution within the puff long after ejection. AIP Publishing LLC 2021-06 2021-06-29 /pmc/articles/PMC8320469/ /pubmed/34335006 http://dx.doi.org/10.1063/5.0054651 Text en © 2021 Author(s). Published under an exclusive license by AIP Publishing. https://creativecommons.org/licenses/by/4.0/All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) ).
spellingShingle ARTICLES
Liu, K.
Allahyari, M.
Salinas, J.
Zgheib, N.
Balachandar, S.
Investigation of theoretical scaling laws using large eddy simulations for airborne spreading of viral contagion from sneezing and coughing
title Investigation of theoretical scaling laws using large eddy simulations for airborne spreading of viral contagion from sneezing and coughing
title_full Investigation of theoretical scaling laws using large eddy simulations for airborne spreading of viral contagion from sneezing and coughing
title_fullStr Investigation of theoretical scaling laws using large eddy simulations for airborne spreading of viral contagion from sneezing and coughing
title_full_unstemmed Investigation of theoretical scaling laws using large eddy simulations for airborne spreading of viral contagion from sneezing and coughing
title_short Investigation of theoretical scaling laws using large eddy simulations for airborne spreading of viral contagion from sneezing and coughing
title_sort investigation of theoretical scaling laws using large eddy simulations for airborne spreading of viral contagion from sneezing and coughing
topic ARTICLES
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8320469/
https://www.ncbi.nlm.nih.gov/pubmed/34335006
http://dx.doi.org/10.1063/5.0054651
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