Get Your CFD Thermal Boundaries Right!
Peter Brady, Principal Engineer, has just published an opinion piece over on LinkedIn about getting your thermal boundary conditions right for CFD. The work sprung from co-supervising a student at UNSW and numerically investigates the effect of thermal stratification of a room and how that drives changes in chimney flow.
The short version: it really, really maters where your thermal boundaries and the boundaries probably have to be much further away than you think.
In the meantime, check out the YouTube playlist of the exploration, it’s a bit long but watch in fast forward. Things get really interesting as the room becomes stratified and hot, low density air is ingested through the throat of the heated chimney.