  Crashing ocean waves, cappuccino froths and microfluidic bubble crystals are
examples of foamy flows. Foamy flows are critical in numerous natural and
industrial processes and remain notoriously difficult to compute as they
involve coupled, multiscale physical processes. Computations need to resolve
the interactions of the bubbles with the fluid and complex boundaries, while
capturing the drainage and rupture of the microscopic liquid films at their
interface. 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 in a waterfall. The present multilayer framework extends the classical
volume-of-fluid methodology and allows for unprecedented large scale,
predictive simulations of flows with multiple interfaces.
