Modelling Droplet Deformation for Sneezing Events using the Eulerian-Lagrangian Particle Surface Approach

Abstract

The Eulerian-Lagrangian approach is widely employed for spray simulations in various applications ranging from transportation systems to environmental flows. Traditional implementations of this technique are based on the assumption that the liquid droplets are spherical. This assumption is unphysical for several applications that droplets vary in shapes. The droplet shape and more specifically the droplet surface affects phenomena like evaporation and drag and consequently the droplet dynamics. Eulerian-Lagrangian simulations have been widely used in the modelling of infectious diseases. Experimental observations on respiratory droplets have shown that during a violent expiratory event, a sneeze, the exhaled saliva forms ligaments of various sizes. Since the shape of the droplets affects the evolution of the spray which in turn determines how far infectious droplets can travel, it is necessary to overcome the spherical assumption limitation in computational models. A novel spray model able to account for the droplet deformation is being developed and it is used in this paper to analyse the droplet deformation during a sneezing event. Results are compared to experimental observations. Such a new model can also be applied to spray injection within ICE or in jets in crossflow relevant to gas turbines.