Drop formation at the surface of plane turbulent liquid jets in still gases

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.