The breakup of levitating water drops observed with a high speed camera

Abstract

Abstract. A wind tunnel was used to interact water drops and were recorded using a high speed camera. Three distinct collisional breakup types were observed and the drop size spectra from each were analysed for comparison with parameterisations constructed by Low and List (1982a). The spectra predicted by the parameterisations did not accurately correlate with the observed breakup distributions for each breakup type when applied to the relatively larger and similarly-sized drop-pairs of size 4–8 mm, comparable to those sometimes observed in nature. We discuss possible reasons for the discrepancies and suggest potential areas for future investigation. A computer programme was subsequently used to solve the stochastic coalescence and breakup equation using the Low and List breakup parameterisation, and the evolving drop spectra for a range of initial conditions were examined. Initial cloud liquid water content was found to be the most influential parameter, whereas initial drop number was found to have relatively little influence. This may have implications when considering the effect of aerosol on cloud evolution, raindrop formation and resulting drop spectra.