Effect of an accelerating metro cabin on the diffusion of cough droplets

Sci Rep. 2024 Jun 19;14(1):14150. doi: 10.1038/s41598-024-64026-3.

Abstract

Coronaviruses being capable of spreading through droplet contamination have raised significant concerns regarding high-capacity public rail transport, such as the metro. Within a rapidly moving railcar cabin, the internal airflow lags behind the bulkhead, generating internally induced airflow that accelerates droplet dispersion within a non-inertial reference system. This study investigates the impact of acceleration on the diffusion of cough droplets of varying sizes using computational fluid dynamics. The modified k-ε equation in ANSYS® Fluent was utilized to simulate droplet diffusion under different body orientations by adjusting the inertial force correction source term. Results indicate that droplets in the middle size range (50-175 μm) are primarily influenced by inertial forces, whereas smaller droplets (3.5-20 μm) are predominantly controlled by air drag forces. Regardless of facial orientation, the outlet of high-capacity public rail transport poses the highest risk of infection.

Keywords: Accelerated cabin; Inertial force; Internal-induced airflow; Metro; coronavirus disease.

MeSH terms

  • COVID-19 / virology
  • Computer Simulation
  • Cough*
  • Diffusion
  • Humans
  • Hydrodynamics
  • Railroads*
  • SARS-CoV-2