Numerical investigation of influence of human walking on dispersion and deposition of expiratory droplets in airborne infection isolation room

This paper introduces a numerical simulation model for investigating the influence of moving subjects on the dispersion and deposition of expiratory droplets, rather than on the dispersion of surrogate gaseous counterparts generally adopted in related research works. In our work, the Lagrangian discrete trajectory model is used for tracing the motion of droplets, the Eulerian RANS method is used for solving the airflow field, and the dynamic mesh model for describing the human movement. The model validation was performed through result comparisons with published data from literatures. A case study on the influence of human walking on the dispersion and deposition of expiratory droplets in an airborne infection isolation room (AIIR) is then presented. Our findings show that the human walking disturbs the local velocity field with wake formation. The increase of walking speed could effectively reduce the overall number of suspended droplets, which may have a positive impact on releasing the infection risk of health workers in AIIR.