Simulation-based study of COVID-19 outbreak associated with air-conditioning in a restaurant

Abstract

COVID-19 has shown a high potential of transmission via virus-carrying aerosols as supported by growing evidence. However, detailed investigations that draw direct links between aerosol transport and virus infection are still lacking. To fill in the gap, we conducted a systematic computational fluid dynamics (CFD)-based investigation of indoor airflow and the associated aerosol transport in a restaurant setting, where likely cases of airflow-induced infection of COVID-19 caused by asymptomatic individuals were widely reported by the media. We employed an advanced in-house large eddy simulation solver and other cutting-edge numerical methods to resolve complex indoor processes simultaneously, including turbulence, flow–aerosol interplay, thermal effect, and the filtration effect by air conditioners. Using the aerosol exposure index derived from the simulation, we are able to provide a spatial map of the airborne infection risk under different settings. Our results have shown a remarkable direct linkage between regions of high aerosol exposure index and the reported infection patterns in the restaurant, providing strong support to the airborne transmission occurring in this widely reported incident. Using flow structure analysis and reverse-time tracing of aerosol trajectories, we are able to further pinpoint the influence of environmental parameters on the infection risks and highlight the need for more effective preventive measures, e.g., placement of shielding according to the local flow patterns. Our research, thus, has demonstrated the capability and value of high-fidelity CFD tools for airborne infection risk assessment and the development of effective preventive measures.

Modeling of aerosol transmission of airborne pathogens in ICU rooms of COVID-19 patients with acute respiratory failure

“…Furthermore, in order to confirm the numerical model’s validity, it would be interesting to collect air and surface samples in different areas of the room of an infected patient, as done to some extent by Santarpia et al 26 and Liu et al 36 . A real time Reverse Transcriptase Polymerase Chain Reaction (rRT-PCR) analysis of these samples would yield results that could confirm the potential danger of aerosol propagation and corroborate the proposed mitigation strategies.…”

“…Some models have also been used to predict the inactivation of airborne pathogens by Ultraviolet C lighting 35 . Additionally, other CFD models were used to predict zones of high exposure to aerosols and link them to areas where infection patterns had been reported in the real-life setting of a Wuhan restaurant 36 . Lagrangian statistics have been used to demonstrate that small droplets’ lifetime is longer than previously expected due to the turbulent humid air expelled with them when breathing or coughing, resulting in increased potential propagation distances 37 .…”

CFD Investigation of Vehicle’s Ventilation Systems and Analysis of ACH in Typical Airplanes, Cars, and Buses

“…The main factors that affect IAQ in the vehicles included the humidity percentage, CO 2 , T, the airflow rate and direction, the type of the utilized air filter [38][39][40], the seat arrangement, and the displacement of ventilation [19,41]. The main approaches for airflow pattern analysis include experimental measurements and CFD simulations [42,43]. In general, to simulate and estimate the parameters, there are several methods, including mathematical, statistical, and numerical techniques [44][45][46][47][48][49].…”

Improving the Energy Efficiency of Buildings Based on Fluid Dynamics Models: A Critical Review

“…A correlation was established between the direct reaching area and the intensities of the coughs. For a restaurant setting, the indoor airflow and the associated aerosol were investigated in [129]. There have been lots of reports by the media on the contamination of asymptomatic COVID-19 cases in similar settings.…”