Figure 3.

A computational fluid dynamics (CFD) prediction of the temperature distribution in a room ventilated by displacement ventilation containing a single individual. The blue colour shows the cold supply flow and the red colour shows the heated air rising to the top of the room. The temperature distribution around the individual can be demonstrated using such a CFD prediction. Air heated in a layer close to the individual (by his/her natural body temperature) rises in a boundary layer, forming a thermal plume above the head. Exhalation flows are visible as horizontal heated flows emanating from the mouth. In the case of an infected person this flow will also contain a variable number of infected droplet nuclei and the plume rising above will also contain bioeffluents (like shed skin scales) released from the body surface. With certain assumptions, a direct prediction of the distribution of small droplet nuclei or larger droplets can also be made with this technique.