While people across the world are practicing social distancing to prevent the spread of coronavirus, the researchers have found that the current social distancing guidelines of 6 feet may be insufficient. Reportedly, a mild cough occurring in low wind speeds of 4-15 kmph can propel droplets to 18 feet.
As per the report published in Physics of Fluids, from AIP Publishing, Talib Dbouk and Dimitris Drikakis discovered that with a slight breeze of 4 kmph, the saliva droplets can travel 18 feet in 5 seconds.
Drikakis said that the droplet cloud will affect both the adults and children of different heights. He added that shorter adults and children could be at higher risk if they are located within the trajectory of the travelling saliva droplets.
Saliva is a complex fluid. It travels suspended in the bulk of surrounding air released by a cough. Many factors affect how saliva droplets travel, including the size and number of droplets and how they interact with one another and the surrounding air as they disperse and evaporate, how heat and mass are transferred, the humidity and temperature of the surrounding air.
To study how saliva travels through the air, Dbouk and Drikakis created a computational fluid dynamics simulation. It examines the state of every saliva droplet travelling through the air in front of a coughing person. The simulation considered the effects of humidity, dispersion forces, interactions of molecules of saliva and air, and how the droplets change from liquid to vapour.