Particles, bubbles and droplets are often small enough that the flow at the scale of the inclusion is predominantly viscous, even when the large-scale dynamics is inertial. This simplifies the governing equations and makes the problem somewhat more tractable. However, in many practical situations, the number of suspended objects is so large, and/or their concentration so high, that they can hardly be treated as isolated elements.

The choice between discrete and continuous representation of the dispersed phase is highly influenced by the tools available to the researcher, from the theoretical, experimental, and numerical standpoint. Those tools rapidly evolve in time, as the great relevance of this class of flows has motivated major recent advances.

This Colloquium will bring together international experts in multiphase dispersed flows, and focus on the following topical questions:

Under which conditions can the discrete object dynamics be up-scaled to represent collective behaviour?
What are the most suitable strategies for the continuous description of the dispersed phase in the various regimes?
Which numerical and experimental methodologies are emerging as the most appropriate for dispersed flows?