PROFESSOR: So in the last part of the course,
we'll discuss the fluid mechanics of indoor spaces,
in particular, going beyond the approximation
of a well-mixed room when considering airborne disease
transmission.
So for example, we will consider the occupants
of a room and their respiratory activity.
So when they breathe, especially if they're not wearing a mask,
or if they cough, they're going to have turbulent plumes
emitting from their mouth, which will then
be convected throughout the room and will influence
other people.
Also, the heat of the body relative to the room
can lead to warmer air, which is rising, so that essentially
sort of a chimney of a thermal plume
rising from an individual.
Those heterogeneities in the flow
and in the concentration of aerosol particles
may not always be well-mixed.
We'll talk about different types of ventilation,
how, for example, cold air will sink from the place
where it's inserted and warm air will rise.
And that may or may not lead to sufficient
mixing to remain well-mixed.
And we'll talk about how to modify our criterion
for airborne disease transmission
in a well-mixed room to account for some of these changes,
in particular the heightened risk of short-range
transmission from being directly in the path
of respiratory puffs and plumes emanating
from an infected person.