Smoke movement driven by a fire under a ceiling

This experimental study shows that the near-field ceiling flow above most fires comprises a succession of very large, distinct and rapidly rotating smoke rolls or vortices. The sense of rotation in these smoke rolls is always the same and the angular velocities are so large that there is a back-flow (towards the fire) in the lower part of each roll. These large-scale structures nominate variations in velocity and temperature and, for this reason, it is important to recognise their characteristics when measuring or modelling fire-driven ceiling flows. Three contrasting model fires have been studied: a pan of flammable liquid, a flaming wood crib, and a smouldering wood crib. Copyright (C) 1996 Elsevier Science Ltd.