Secondary breakup of a drop at moderate Weber numbers

作者：Jain Mohit; Prakash R Surya; Tomar Gaurav^*; Ravikrishna R V

来源：Proceedings of the Royal Society A-Mathematical Physical and Engineering Sciences, 2015, 471(2177): 20140930.

DOI：10.1098/rspa.2014.0930

• atomization
• secondary breakup
• droplets
• high density ratio

We present volume of fluid based numerical simulations of secondary breakup of a drop with high density ratio (approx. 1000) and also perform experiments by injecting monodisperse water droplets in a continuous jet of air and capture the breakup regimes, namely, bag formation, bag-stamen, multibag and shear breakup, observed in the moderate Weber number range (20-120). We observe an interesting transition regime between bag and shear breakup for We = 80, in both simulations as well as experiments, where the formation of multiple lobes, is observed, instead of a single bag, which are connected to each other via thicker rim-like threads that hold them. We show that the transition from bag to shear breakup occurs owing to the rim dynamics which shows retraction under capillary forces at We = 80, whereas the rim is sheared away with flow at We = 120 thus resulting in a backward facing bag. The drop characteristics and timescales obtained in simulations are in good agreement with experiments. The drop size distribution after the breakup shows bimodal nature for the single-bag breakup mode and a unimodal nature following lognormal distribution for higher Weber numbers.

• 出版日期2015-5-8