[ad_1]
Dispersion of large, medium and small cough drops in the air under different external conditions.
The ongoing COVID-19 pandemic has led many researchers to study the transmission of airborne droplets under different conditions and in different environments. The latest studies are beginning to consider important aspects of fluid flow physics to deepen our understanding of virus transmission.
In a new article in AIP Publishing’s Physics of Fluids, researchers from the A * STAR Institute for High Performance Computing performed a numerical study of droplet dispersion using high-fidelity airflow simulation. Scientists have found that a single 100-micron cough drop can travel up to 6.6 meters with a wind speed of 2 meters per second and even more in dry air conditions due to evaporation of the droplets.
“In addition to wearing a mask, we have found that social distance is generally effective, as it has been shown to reduce the accumulation of droplets in a person at least 1 meter away from the cough,” said lead author Fong Yew Leong.
The researchers used computational tools to solve complex mathematical formulations representing the flow of air and airborne cough drops around the human body at different wind speeds and when they are affected by other environmental factors. They also assessed a person’s deposition profile in a particular area.
A typical cough emits thousands of droplets over a wide range of sizes. Scientists found that large droplets quickly settle to the ground due to gravity, but could also be projected 1 meter from the windless cough stream. Medium-sized droplets could evaporate into smaller droplets that are lighter and easier to carry in the wind, and these would continue to travel.
Researchers provide a more detailed picture of droplet dispersion because they incorporated biological considerations of the virus, such as the non-volatile content of droplet evaporation, into modeling the dispersion of airborne droplets.
“One drop that vaporizes keeps the virus content non-volatile, so the viral load has actually increased,” said lead author Hongying Li. “This means that vaporized droplets that become aerosols are more likely to be inhaled deeply into the lungs, causing infections further down the airways than larger non-evaporated droplets.”
These results are also highly dependent on environmental conditions such as wind speed, humidity and ambient air temperature, and are based on existing scientific literature assumptions about the feasibility of the COVID-19 virus.
Although this research has focused on airborne transmission in a tropical setting, the scientists intend to apply their findings to assess risk in indoor and outdoor areas where crowds gather, e.g. B. in conference rooms or amphitheaters. The research could also be applied to the design of environments that optimize comfort and safety, such as: B. Hospital rooms that take into account the internal air flow and the transmission of airborne pathogens.
Reference: “Vaping Cough Drop Dispersion in a Tropical Outdoor Environment” by Hongying Li, Fong Yew Leong, George Xu, Zhengwei Ge, Chang Wei Kang, and Keng Hui Lim, November 3, 2020, Physics of Liquids.
DOI: 10.1063 / 5.0026360.
Source link
