Contribution of the Hydraulics group of the Polytechnic University of Bari to the fight against COVID-19

In the face of the increasing death toll from the COVID-19 global pandemic, countries around the world have instituted restrictive measures to mitigate the serious effects of the pandemic. Human-to-human transmission of COVID-19 occurs primarily through large droplets that are expelled with sufficient momentum to directly contact the recipients’ mouth. Therefore, the physics of flow is central to transmission of COVID-19. Respiratory infections increase the frequency of violent expiration, including coughing and sneezing, which are particularly effective in dispersing virus-carrying droplets. Moreover, the high viral load in droplets of asymptomatic hosts that are expelled during respiratory activities, is contributing to the rapid growth of COVID-19 global pandemic. The present study uses 2D smoothed-particle-hydrodynamics multiphase simulations of the fluid dynamics of violent expiratory events in order to obtain a deeper understanding of the multi-phase nature of respiratory clouds, which can help determine separation distances from an infected person needed to minimize respiratory transmission.

First results are shown in this paper:

Diana De Padova and Michele Mossa, Multi-phase simulation of infected respiratory cloud transmission in air, AIP Advances 11, 035035 (2021)

which can be downloaded from this link: https://doi.org/10.1063/5.0047692

The movie shows an example of the sneeze dynamics. Apart from the case of the video, the simulations have shown different phases of coughing and sneezing and that the safety distance can be greater than the canonical one used for the so-called social distancing.