Articles producció científica> Enginyeria Mecànica

Direct numerical simulation of the turbulent flow generated during a violent expiratory event

  • Dades identificatives

    Identificador: imarina:9178048
    Autors:
    Fabregat, AlexandreGisbert, FerranVernet, AntonDutta, SomMittal, KetanPallares, Jordi
    Resum:
    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.
  • Altres:

    Autor segons l'article: Fabregat, Alexandre; Gisbert, Ferran; Vernet, Anton; Dutta, Som; Mittal, Ketan; Pallares, Jordi;
    Departament: Enginyeria Mecànica
    e-ISSN: 1089-7666
    Autor/s de la URV: Fabregat Tomàs, Alexandre / Pallarés Curto, Jorge María / Vernet Peña, Antonio
    Paraules clau: 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
    Resum: 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.
    Àrees temàtiques: 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
    Accès a la llicència d'ús: https://creativecommons.org/licenses/by/3.0/es/
    ISSN: 1070-6631
    Adreça de correu electrònic de l'autor: alexandre.fabregat@urv.cat anton.vernet@urv.cat jordi.pallares@urv.cat
    Identificador de l'autor: 0000-0002-6032-2605 0000-0002-7028-1368 0000-0003-0305-2714
    Data d'alta del registre: 2024-07-27
    Versió de l'article dipositat: info:eu-repo/semantics/publishedVersion
    Enllaç font original: https://aip.scitation.org/doi/10.1063/5.0042086
    URL Document de llicència: https://repositori.urv.cat/ca/proteccio-de-dades/
    Referència a l'article segons font original: Physics Of Fluids. 33 (3): 035122-1-035122-12
    Referència de l'ítem segons les normes 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
    DOI de l'article: 10.1063/5.0042086
    Entitat: Universitat Rovira i Virgili
    Any de publicació de la revista: 2021
    Tipus de publicació: Journal Publications
  • Paraules clau:

    Computational Mechanics,Condensed Matter Physics,Engineering (Miscellaneous),Fluid Flow and Transfer Processes,Mechanical Engineering,Mechanics,Mechanics of Materials,Physics, Fluids & Plasmas
    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
    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
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