Direct numerical simulations show deficiencies in barriers against airborne viral spread
DOI: 10.1063/10.0009041
Direct numerical simulations show deficiencies in barriers against airborne viral spread lead image
The COVID-19 pandemic has spurred a number of studies investigating the mechanisms of airborne virus transmission in both open space and indoor environments. Many reveal that ambient humidity and fluid turbulence represent considerable variables in determining the lifetime of virus-containing droplets.
A new study employs direct numerical simulations (DNS) to consider these variables in examining the effect of barriers, recommended by the World Health Organization to help prevent infections, on the airborne spread of virus-containing droplets in indoor environments.
Cavaiola et al. use DNS to simulate a human cough in a closed room from various distances at which a barrier is placed, and consider two different values, dry and wet, corresponding to relative humidity levels of 30% and of 60%, respectively. To assess risk of transmission, the viral load in exhaled droplets is quantified by tracking the position of each droplet for the entire simulation time.
“We show that barriers, while reducing the airborne viral load, cause nontrivial dynamical effects influencing the final reach of the virus-containing droplets, not always beneficial to the final aim of preventing infection,” said co-author Mattia Cavaiola. “For example, the closest barrier facilitates large droplets to be removed from the air, but, as a side effect, the final reach of the smallest droplets not captured by the barrier is larger than what is observed in the cases with a greater barrier distance.”
The research provides other physically based results pertaining to the efficacy of barriers.
“Although our study is motivated by the current pandemic, its results are applicable to all infections transmitted primarily via airborne virus-containing droplets,” said Cavaiola.
Source: “Role of barriers in the airborne spread of virus-containing droplets: A study based on high-resolution direct numerical simulations,” by M. Cavaiola, S. Olivieri, J. Guerrero, A. Mazzino, and M. E. Rosti, Physics of Fluids (2021). The article can be accessed at https://doi.org/10.1063/5.0072840 .
