Influence of the ventilation strategy on the respiratory droplets dispersion inside a coach bus: CFD approach

Abstract The airborne transmission of the COVID-19 virus was considered main cause infection. increasing concern about spread in confined spaces, characterized by high crowding indexes and an often-inadequate air exchange system, pushes scientific community to design many studies aimed at improving indoor quality. risk depends on several factors such as droplet properties, characteristics, airflow patterns. route SARS-CoV-2 humans is respiratory through small (<100 μm) large droplets. In environment, plays a fundamental role dispersion this study, integrated approach developed evaluate influence ventilation strategy droplets emitted inside coach bus. There are no specific guidelines standards rate (AER) values be respected environments buses. aim work analyse concentration distribution Ansys FLUENT used numerically solve well-known transient Navier-Stokes equations (URANS equations), energy equation using Lagrangian Discrete Phase Model (DPM) construct trajectories. geometry representative intercity bus, vehicle constructed exclusively for carriage seated passengers. 3D CAD model represented bus with HVAC within which infected subject present. positions exhaust vents air-conditioning were chosen ensure complete circulation throughout well-defined size mass mouth. provided two different ways: general (from intakes positioned along windows top side central corridor) personal (with each passenger). For single AER value set (0.3 m 3 s −1 ). first results obtained showed slight particle computational domain due entered but still elevated level tended accumulate area near subject. Additional analysis executed beneficial effects linked further addition placed above every passenger’s head. show importance use system highlighting how contribution can lead significant reduction exposure consequently infection from diseases.