Large-scale 3D flow investigations around a cyclically breathing thermal manikin in a 12 m³ room using HFSB and STB

Abstract

Bioaerosol transport, dispersion and (local) accumulation processes in closed rooms have been identified as the main reasons for indirect or airborne SARS-CoV-2 transmission from person to person (Morawska and Cao 2020). Understanding short- and long-term airborne transport mechanisms of viruses via small bioaerosol particles (< 5 µm) inside populated rooms is an important key factor for optimizing various mitigations strategies (Morawska et al. 2020). Therefore, a large-scale 3D Lagrangian Particle Tracking (LPT) experiment enabling the instantaneous tracking of up to ~3 million submillimeter helium-filled-soap-bubbles (HFSBs) as passive tracers in a 12 m³ generic test room has been performed at DLR Göttingen, which allows to fully resolve the flow field in the complete room around a heated cyclically breathing thermal manikin with and without mouth-nose-masks or shields applied (see Figure 1). Six high-resolution CMOS streaming cameras (50 and 25 MP), an array of powerful pulsed LEDs and the Shake-The-Box (Schanz et al. 2016) LPT algorithm have been combined.