NUMERICAL INVESTIGATION OF COLLISION-INDUCED BREAKUP OF RAINDROPS. PART I: METHODOLOGY AS WELL AS DEPENDENCIES ON COLLISION ENERGY AND EXCENTRICITY

Numerical investigations of binary raindrop collisions, comprising the drop pairs of Low and List (1982a), have been performed using a DNS tool based on the Volume-of-Fluid method. Looking at the coalescence efficiencies as well as the number and sizes of the fragment droplets, both agreement and discrepancies between the numerical simulations and the experimental data of Low and List (1982a) are observed. The results show that the size distribution of fragments is dependent on the collision energy and is shifted to smaller fragments for higher energies. In the second part of this paper, Straub et al. (2008) present new parameterizations of coalescence efficiencies and fragment size distributions based on the results obtained.