An experimental study of drop formation at the free surface of plane turbul
ent jets in gases (i.e., turbulent primary breakup) is described. Test cond
itions consisted of fully-developed turbulent plane water jets injected int
o still air at standard temperature and pressure with Reynolds numbers of 9
1,000-424,000, Weber numbers of 13,000-151,000 and Ohnesorge numbers of 0.0
009-0.0012. Pulsed shadowgraphy was used to measure mean liquid surface vel
ocities, mean and fluctuating drop velocities after primary breakup, drop s
izes after primary breakup and the location of the onset of primary breakup
. Drop velocities were related to the average streamwise velocity in a rela
tively simple manner, while drop size properties could be related to earlie
r findings for turbulent primary breakup of round liquid jets in still gase
s using hydraulic diameter concepts. (C) 1999 Elsevier Science Ltd. All rig
hts reserved.