Soft Matter and Complex Systems Seminar

The mechanism responsible for rain in warm (i.e., ice-free) clouds is collision-coalescence among cloud droplets. Field observations show that rain showers can develop very quickly, on time scales much shorter than typical collision times predicted by theories that neglect air flow turbulence. Several effects of turbulence may reduce the time for warm rain initiation. This talk focuses on the effect of local clustering of inertial droplets that interact hydrodynamically. Quantitative description of turbulent collision of droplets represents a major unresolved problem in cloud physics.