Of Rainfall and Marine Snow: How Small-Scale Physical Interactions have Large-Scale Consequences

The large-scale flows in our environment are rife with tiny dispersed droplets, particles or bubbles. Oftentimes the mutual interactions between the dispersed phase can cause large-scale processes: rain formation in clouds or the formation of marine snow in oceans. The reverse interaction of the dispersed phase on the flow can be dramatic: in turbidity currents the clustering of tiny particles leads to the generation of destructive currents on the ocean floors. In all cases the large, intermediate and small scales are intimately coupled. A true multiscale description is required.

These multidisciplinary problems require a combined effort of various expertises from different fields (cloud physics, aquatic ecology, geology, etc.). It is our intention to gather such a multidisciplinary audience for this workshop, to combine knowledge and methods and to foster joint efforts in this wide open field. The concrete questions that we want to address in this meeting are:

* What is the relation between the fluid-flow turbulence and the aggregation, coalescence or breakup of the dispersed phase, and how can this interplay be modelled?

* How can we validate such models using laboratory-scale experiments and/or observations?

* How do mesoscopic physical processes, like phase changes or adsorption, affect the behaviour of the   dispersed phase, and how can they be modelled for efficient numerical simulation?

Confirmed Invited speakers:

Gregory Bewley (MPI Göttingen) - experiments on droplets in turbulence

Lance R. Collins (Cornell) - simulation and modelling of droplet ensembles in turbulence

Ármann Gylfason (Reykjavik) - multiphase wind tunnel

Alessandra Lanotte (CNR-ISAC, Lecce)

Ellen Longmire (University of Minnesota)

Federico Maggi (Sydney) - occulation and sedimentation

Eckart Meiburg (Santa Barbara) - turbidity currents

Raymond A. Shaw (Michigan Tech) - atmospheric measurements

Ryo Onishi (Earth Simulator Center Japan) - numerical simulation of droplets in turbulence

Fabrice Veron (Delaware) - ocean spray