Interim Provost and Dean of the College of Engineering and Applied Sciences delivered a virtual lecture addressing: “How Far Is Far Enough and Can Masks Curb the Spread of COVID-19?” More than 225 participants joined the December 2 event live via Zoom as part of the Provost Lecture “Spotlight on COVID-19” series.
With an introduction by Dr. Kenneth Kaushansky, Senior Vice President for Health Sciences and Dean, Renaissance School of Medicine, Sotiropoulos began by discussing ways of building on the success of Stony Brook’s return to campus for the fall semester, and a means toward an eventual return to normal activity at Stony Brook.
Sotiropoulos began with an overview of his career-focused research on computational fluid mechanics challenges in energy, environment, geology and health, which includes the spreading of respiratory viruses. He focused on new Stony Brook research studying insights on effective social distance and face coverings gained by numerical simulation, conducted by a team in the Department of Civil Engineering that includes assistant professor Ali Krosronejad, research associate Christian Santoni and PhD students Kevin Flora and Zexia Zhang.
Sotiropoulos described the importance of fluid mechanics to the spread of a virus like COVID-19. A virus is primarily spread by respiratory droplets produced by exhalation. As we exhale, sneeze and cough it creates a range of particles at a range of scales. Some droplets are visible and some are not. The process of creating these droplets begins in the airways of the respiratory system, resulting in different modes of transmission depending on size of droplets and whether it is transmitted via surfaces or airborne. Airborne transmission occurs more easily when droplets are very small and stay suspended for a long period of time and can be inhaled and penetrate lung tissues, which is the case with coronavirus.
WHO and CDC social distancing guidelines were based on outdated science focusing on potential transmission through contaminated surfaces, Sotiropoulos said. Larger, heavy saliva particles can in fact settle within the recommended six-foot CDC guidelines and could contaminate surfaces. However, the greater concern is the smallest particles, or “aerosols,” that can be transported by the airflow several feet away from the body and stay suspended for longer periods of time.
The research used computational fluid dynamics modeling for coughing and breathing, indoors and outdoors, with masks and without. High-fidelity numerical simulations of respiratory particulate transport on high-performance supercomputers provided strong evidence that even the simplest masks are effective in protecting others by dissipating the forward momentum of expiratory jets, especially in indoor environments. The details of the study were just published in a paper, entitled “Fluid dynamics simulations show that facial masks can suppress the spread of COVID-19 in indoor environments,” in American Institute of Physics (AIP) Advances (Vol.10, Issue 12). The article is freely available to the public in this open access journal and may be accessed at https://doi.org/10.1063/5.0035414.
“The difference is stunning,” Sotiropoulos said. “Masks can modify the structure of a cough and dramatically diminish its energy and forward propagating momentum. The bottom line is: Wear a mask, any mask, and stay six feet apart to both protect yourself and others around you.”
— Chris Maio
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