09-09-2021 | Posted by Joaquín Martí
The world has lived with covid-19 for about a year and a half. Its impact has been and still remains enormous: on the health side, fatalities, hospitalisations, and all kinds of sequels; on the economy in general, and certain sectors in particular, it has been dramatic; even our way of life and social customs have been drastically affected.
Every cloud, however dark, has a silver lining. The pandemic has generated unprecedented worldwide scientific collaboration, leading to new developments in record time, lots of lateral thinking, and considerable learning, often from initial mistakes.
Consider, for example, the initial advice by WHO, also echoed by the Spanish government, discouraging the use of face masks by the general public. This was based on a believe that short-range encounters and infected surfaces were the main infection routes. WHO now recommends wearing a face mask and our government has made it compulsory to do so in public places.
It turns out that the main route for infection seems to be airborne. Because exhaled breath is a moist, hot, turbulent cloud of air, a 5-micron droplet released at a height of 1.5 metres can be carried tens of metres before settling. Also, liquid drops of all sizes, including those defined as aerosols, are being continuously shed; coughing or sneezing projects large numbers of droplets, but talking, and even just breathing, also releases them.
Physicists have shown that particles below 100 microns can become airborne, which implies that hand-washing and social distancing, though important, are not enough to stop an airborne virus spreading, especially indoors. Masks help, by slowing down and partially filtering infectious exhalations, but to keep indoor spaces safe also requires improvements in their ventilation.
It is then key to understand the transport of contaminated droplets. Simulation can model airflow through vehicle interiors, aircraft cabins and buildings, and predict how far droplets can go. This information can then be used to design efficient shields and personal protective equipment (PPE), or to assess the layout of a living/working space to ensure distancing, or to optimize ventilation and filtration systems to remove viral particles from the air or, at least, prevent them from contaminating clean areas.
Accurate cough simulation requires a solver capable of modelling both the airflow and the particle behaviour of the droplets. SIMULIA CFD/Fluid Solutions, powered by key technologies such as PowerFLOW y XFlow, can accurately model turbulent airflow, particle motion and tracking, as well as surface deposition, in complex environments. With thermal and acoustic simulation capabilities, SIMULIA CFD/Fluid solutions allow modelling droplet propagation in combination with heating, ventilation, and air-conditioning, to guarantee safety while maintaining comfort.
The Dassault Systèmes 3DEXPERIENCE® business platform provides easy sharing of data and collaboration. This has many advantages for accelerating innovation, and it is especially useful in ensuring business continuity when business travel is impossible and many employees are working from home.
The 3DEXPERIENCE cloud computing capability also gives users access to high-performance computing clusters that they cannot otherwise access at home. To help customers who are new to this kind of simulation, Dassault Systèmes has developed an “Outcome-Based Services” approach, where our engineers collect data for customers without the resources or experience to run the simulations. Customers focus on their challenges and our experts run the simulations to provide customers with valuable operational results.
If you have any queries, we at Principia have the professionals with the desire to help and the expertise to do it successfully.
