Corona Virus Spread due to a Cough in Open Air

Corona Virus Spread due to a Cough in Open Air, ANSYS Fluent CFD Simulation Training

The present problem aims to simulate coronavirus spread due to human cough in the open air using ANSYS Fluent software.

This spreads the virus particles in the open air and can infect a person at a certain distance from the patient.

Therefore, one of the most up-to-date topics that researchers are constantly researching is calculating and examining the minimum appropriate distance between a sick person and a healthy person to prevent the spread and transmission of viruses when a patient coughs or sneezes, called social distancing or physical distancing.

This model involves a human placed in a cube-shaped computational domain as the open air, and the human mouth is distinguished as a source of virus transmission.

The present 3-D model is designed using SOLIDWORKS and Design Modeler software.

The model meshing has been done using ANSYS Meshing software, and the mesh type is unstructured. The mesh accuracy is higher in areas close to the patient’s mouth than elsewhere. The element number is 584587.

CFD Methodology

This project uses a two-way discrete phase model (DPM). The behavior of discrete phase particles in the unsteady state is also defined, and it is also assumed that the behavior of the particles is affected by the continuous flow (interaction with continuous phase).

The physical states defined for the discrete phase model include stochastic collision, coalescence, and breakup. These droplets have a temperature of 310 K, a velocity of 31.85 m.s-1, and a flow rate of 0.018 kg.s-1, which are emitted in the interval of 0 s to 0.1 s.

The diameters of these particles are not constant and equal to each other; therefore, the rosin-rammler-logarithmic distribution method is considered for the size of the diameters. Determine the minimum, maximum and middle diameter size, spread parameter and the number of diameters per injection.

It should be noted that the droplet mode is applied when the species model is enabled. In this model, the mode of species transport is activated to simulate the droplet and evaporation; thus, the working space of the model around the patient will have airflow.

According to the definition of injection, virus particles from a human cough are physically expelled from the mouth by water droplets evaporating in space.

Corona Virus Spread Due to a Cough Conclusion

At the end of the solution process, we obtain the particle tracking of the virus particles. This particle sequence is based on the output resistance time. We take out the animation of the virus release and its disappearance over time.

Also, we obtain and present the images related to the virus particle sequence at different times. The results show the virus spread during the patient’s cough, which occurs in the open air from 0.1 s to 1.75 s.