Executive Summary : | The impact of the COVID-19 epidemic across India and other foreign nations caused devastating losses to the economy, social care and more importantly human lives. Thus the need for better medical care has led to scientific advancements where classic engineering tools are now used in the biomedical field to study the transmission of diseases. State of the art supercomputers and numerical algorithms allow us to study the transmission of particles and fluids in multiphase flows to prevent the spread of airborne and waterborne infections.
Viruses may be transmitted through breathing, speaking or coughing via aerosols suspended in a gaseous medium which constitutes the two-phase fluid medium flowing out of a human being’s mouth. The virus travels through the suspended medium and may infect others by entering into another person’s internal system in an airborne manner. Thus it is important to study the underlying mechanisms that govern the flow of speech jets when a person utters a specific phrase or sentence. The sounds governing the speech uttered then determines how far the speech travels and which trajectory. Thus providing us an insight as to how to measure the rate of being infected by the virus. In this project we would like to study the probability of being affected by an airborne infection with respect to SARS-CoV-2 using an Euler-Lagrange CFD algorithm. Viruses may be transmitted through regular speech flow via aerosols suspended in a gaseous medium which constitutes the two-phase fluid medium flowing out of a human being’s mouth. The virus travels through the suspended medium and may infect others by entering into another person’s internal system in an airborne manner. Many prior studies have considered speech flows to be essentially single-phase where the aerosols are assumed to be droplets whose characteristic size is much smaller than the characteristic size of the speech jet. The shortcomings from a fully Eulerian model can be mitigated by considering a more sophisticated model where the aerosols are treated as a separate medium. The discrete phase is treated individually where each droplet is accounted for using a Lagrangian mesh. The interaction between the carrier fluid and each droplet is treated by placing the Lagrangian mesh onto the continuum Eulerian mesh and solving for the transport equations governing both the gas phase and discrete phase by coupling the two systems of equations using closures for drag, heat and mass transport. Such Euler-Lagrange models provide a more accurate insight into the flow phenomena.
By studying the accurate flow profile of the droplets we may estimate the time taken for the transmission of all the aerosols to the opposite end of the speech domain. We can also calculate the trajectory of flow and predict the total volume of aerosol content advected to an opposing person at the other end. This allows us to estimate the probability of another person being infected with the disease. |