CFD SIMULATION OF A COUGHING DROPLET DIFFUSION IN THE ACCELERATING-MOTION METRO CABIN

Abstract. The metro cabin provides an effective way for the spread of the pneumonia virus when provides convenience to human beings. The cabin undergoes a series of motions of acceleration speed, uniform speed, and deceleration speed during the one-station travelling process. The induced flow of the accelerated moving cabin is the determinant of the air drag force on the cough droplets, and effect on the time-frequency characteristics and motion trajectories of droplets of different sizes. In this study, we established a momentum equation on droplets, affected by the inertial force correction term in the non-inertial frame. Then added the drag force from the velocity difference between the cough droplets and the background airflow, and simulated configurations as: 1) droplet spreading aerodynamic process from different face orientations of infected dummy, 2) six groups of size particles, and 3) variable speed motion phases. The numerical simulation provides a physical analysis idea for studying the relationship between the two-phase flow under the action of inertial force. This design of a ventilation environment in public transportation helps to reach a more profound understanding of the inertial precipitation mechanism of droplet jets.