Cover illustration: Non-premixed hydrocarbon flame
This year's cover illustration, reproduced here as figure 1, depicts an image formed by a short time (1/1000 s) exposure of a non-premixed hydrocarbon flame. The flow is driven by buoyancy forces generated by the density difference from the combustion heat released and resulting temperature rise. The Reynolds number for this buoyancy-induced, turbulent flow is relatively low, estimated at a few thousand.
Fig. 1. Non-premixed hydrocarbon flame. ©1971 Paul E Dimotakis.