Direct numerical simulation of pathogen-laden aerosol dispersion in buoyancy-driven turbulent flow within confined spaces

Identifier:  imarina:9414292

Handle: https://hdl.handle.net/20.500.11797/imarina9414292

Authors:  Lavrinenko, A; Fabregat, A; Gisbert, F; Pallares, J

Abstract:
Turbulent dispersion of particles is vital in understanding the transmission of airborne infectious diseases. Transmission primarily occurs via inhalation of pathogen-laden aerosols released when infected individuals breathe, talk, cough, or sneeze. We employ Direct Numerical Simulations to investigate aerosol dispersion in an idealized cubic room subjected to high Rayleigh numbers induced by natural convection. Temperature difference on opposing walls drive turbulent flow with a dominant large-scale recirculation. The initial aerosol distribution consists of spherical solid particles (0.1-2.5 mu m in diameter) randomly seeded within a spheres initially located on the main diagonal of the cavity. Analysis of particle relative dispersion and concentration variance reveals strong inhomogeneity, highlighting lower dispersion in the central area of the room and significantly higher dispersion near the walls. Additionally, we introduce a new analytical model for aerosol cloud dispersion within the cubic room, comparing it with Direct Numerical Simulations. Results suggest that closed-form models in some cases provide reasonable estimates of particle mixing time. According to simulation results, homogeneous mixing inside the room is attained 500 s after the release even for the most unfavorable conditions. This research advances our comprehension of indoor aerosol dispersion, a critical factor for evaluating the risks associated with airborne disease transmission.