Computing foaming flows: from microfluidic crystals to breaking waves*

Foamy flows are critical in numerous  natural and industrial processes and remain notoriously difficult to compute as they involve coupled, multiscale physical processes. The simulation of foamy flows, involving non-coalescing bubbles, presents a number of formidable challenges, in addition to those associated with resolving the bubble interactions with the fluid flow and the solid boundaries.  We present a novel multilayer simulation framework (Multi-VOF)  that advances the state of the art in simulation capabilities of foamy flows. The framework  introduces a novel scheme for the distinct handling of multiple neighboring bubbles and a new regularization method that produces sharp interfaces and removes spurious fragments. Multi-VOF is verified and validated with experimental results and complemented with open source, efficient scalable software. We demonstrate capturing of bubble crystalline structures in realistic microfluidics devices and foamy flows involving tens of thousands of bubbles.