Fast MILES solver: validation of a new scalable tool to study and optimize indoor ventilation

Indoor displacement ventilation systems have several important functions for occupants such as thermal comfort, supply of fresh air and reduction of contaminants exposure, and they have been favored in parts of the world for their energy-efficiency. Indeed, the flow rate of such a ventilation system is driven by the buoyancy induced by the heat output of the occupants. In the context of respiratory infectious diseases, improvement of indoor ventilation is key for the reduction of transmission, as clearly demonstrated yet again during the COVID-19 pandemic.



The most accurate Direct Numerical Simulation (DNS) of displacement ventilation flows is very expensive and impractical for large geometries. We demonstrate how a Monotonically Integrated Large Eddy Simulation (MILES) could be used as a cheaper alternative for the simulation of such flows.



We compare the results from MILES to gold-standard DNS simulations, discuss the validity and limitations of the MILES approach to address questions of indoor airflow patterns in larger indoor spaces, and illustrate the approach by simulating air flow patterns in a large auditorium. Although further validation is required before the tool can be used for risk assessment, it has the potential to bridge the gap between prohibitively expensive flow simulations preventing case comparisons at scale, and overly simplistic models relying on perfectly-mixed conditions, which are known to lead to erroneous indoor risk assessments.