the Distance of two meters will not save you from being infected with coronavirus, warning the Cyprus physics. Microdroplets of saliva ejected during sneezing, coughing or even talking capable of using the wind to move to a distance three times greater in just 1.6 seconds.
the distance of two meters is too low, to avoid being infected with coronavirus, experts warn the University of Nicosia in Cyprus. The viral particles are carried by air currents much further and is able to overcome longer distances in a few seconds. The study was published in the journal Physics of Fluids.
“Our understanding of the mechanisms of transmission of viruses through the air incomplete, the authors write operation. — In this article to calculate the transport, dispersion and evaporation of particles of saliva, resulting from a coughing person, used computational multiphase fluid dynamics and heat transfer. The process of ejection of droplets of saliva in the air simulates a real human cough.”
the Saliva gets into the air by coughing, sneezing and even talking. For a moving particle is affected by many factors, including the size and number of drops as they interact with each other and with the surrounding air as dissipate and evaporate, what is the humidity and the ambient air temperature is , etc.
To find out, as the saliva moves in the air, the authors established the hydrodynamic simulation that tracks the movement of every drop of saliva off of his mouth. During the simulation the researchers took into account the effect of humidity, dispersion of droplets, interaction of molecules of saliva and air, and how the drops are converted from liquid to vapor. They modeled the movement of more than thousands of drops of saliva.
If the wind speed is 15 km/h, the saliva will overcome six metres in 1.6 seconds. Gradually, the cloud droplets will fall, so the affected area will be children and small people.
All this makes the distance of two meters ineffective — even if the infected person will cough and sneeze right in your face healthy, virus particles can still reach it by air.
coughing is thrown around 3,000 droplets of saliva, by sneezing — up to 40 thousand., warn researchers.
“the Cloud drops will touch adults and children have different growth, says physicist Dimitris Drikakis, one of the authors of the work. — Children and stunted adults may be at higher risk if they are within the trajectory of the drops of saliva”.
Further research is needed to determine the effects of temperature of the earth’s surface to the behavior of saliva in the air and to study the behavior of saliva in premises where the ventilation system significantly affects the motion of particles of saliva in the air, stress Spa��iality.
“This work is vital, since it concerns a safe distance between people during a pandemic, contributes to the understanding of the spread of diseases transmitted airborne by and helps to shape the precautions, based on scientific results,” concludes Drikakis.
the Belgian physicist Bert Blocken from the Technical University of Eindhoven previously calculated that runners and cyclists need to stay further away — they “train” droplets, which may contain virus, can reach 20 m.
“When somebody breathes, coughs or sneezes while walking, running or Cycling, a large part of the microdroplets is behind the man — said Broken. And someone who walks, runs or rides him, is in this air flow and moves through a cloud of drops.”
If a person is running, you must retreat 10 metres, the cyclist must be at a distance of 20 m.
Another way to avoid falling into the flow — to leave a couple of feet to the side. When overtaking Broken recommends you make sure the person who will be behind you, you will not get in your “zone”.
