Author, as appears in the article.: Fabregat, Alexandre; Gisbert, Ferran; Vernet, Anton; Dutta, Som; Mittal, Ketan; Pallares, Jordi;
Department: Enginyeria Mecànica
e-ISSN: 1089-7666
URV's Author/s: Fabregat Tomàs, Alexandre / Pallarés Curto, Jorge María / Vernet Peña, Antonio
Keywords: Vortex flow Viruses Turbulent vortices Turbulence intensity Trajectory prediction Three-dimensional structure Temperature differences Severe acute respiratory syndrome coronavirus Numerical models Hydrodynamics Diseases Direct numerical simulation Background flow Atmospheric movements Analytical models Air Aerosols Aerosol dispersion
Abstract: A main route for SARS-CoV-2 (severe acute respiratory syndrome coronavirus) transmission involves airborne droplets and aerosols generated when a person talks, coughs, or sneezes. The residence time and spatial extent of these virus-laden aerosols are mainly controlled by their size and the ability of the background flow to disperse them. Therefore, a better understanding of the role played by the flow driven by respiratory events is key in estimating the ability of pathogen-laden particles to spread the infection. Here, we numerically investigate the hydrodynamics produced by a violent expiratory event resembling a mild cough. Coughs can be split into an initial jet stage during which air is expelled through mouth and a dissipative phase over which turbulence intensity decays as the puff penetrates the environment. Time-varying exhaled velocity and buoyancy due to temperature differences between the cough and the ambient air affect the overall flow dynamics. The direct numerical simulation (DNS) of an idealized isolated cough is used to characterize the jet/puff dynamics using the trajectory of the leading turbulent vortex ring and extract its topology by fitting an ellipsoid to the exhaled fluid contour. The three-dimensional structure of the simulated cough shows that the assumption of a spheroidal puff front fails to capture the observed ellipsoidal shape. Numerical results suggest that, although analytical models provide reasonable estimates of the distance traveled by the puff, trajectory predictions exhibit larger deviations from the DNS. The fully resolved hydrodynamics presented here can be used to inform new analytical models, leading to improved prediction of cough-induced pathogen-laden aerosol dispersion.
Thematic Areas: Química Physics, fluids & plasmas Mechanics of materials Mechanics Mechanical engineering Materiais Matemática / probabilidade e estatística Interdisciplinar Geociências Fluid flow and transfer processes Engineering (miscellaneous) Engenharias iv Engenharias iii Engenharias ii Engenharias i Condensed matter physics Computational mechanics Ciências biológicas i Ciência da computação Astronomia / física
licence for use: https://creativecommons.org/licenses/by/3.0/es/
ISSN: 1070-6631
Author's mail: alexandre.fabregat@urv.cat anton.vernet@urv.cat jordi.pallares@urv.cat
Author identifier: 0000-0002-6032-2605 0000-0002-7028-1368 0000-0003-0305-2714
Record's date: 2024-07-27
Papper version: info:eu-repo/semantics/publishedVersion
Link to the original source: https://aip.scitation.org/doi/10.1063/5.0042086
Licence document URL: https://repositori.urv.cat/ca/proteccio-de-dades/
Papper original source: Physics Of Fluids. 33 (3): 035122-1-035122-12
APA: Fabregat, Alexandre; Gisbert, Ferran; Vernet, Anton; Dutta, Som; Mittal, Ketan; Pallares, Jordi; (2021). Direct numerical simulation of the turbulent flow generated during a violent expiratory event. Physics Of Fluids, 33(3), 035122-1-035122-12. DOI: 10.1063/5.0042086
Article's DOI: 10.1063/5.0042086
Entity: Universitat Rovira i Virgili
Journal publication year: 2021
Publication Type: Journal Publications
Repositori URV