  This paper presents an enhancement to the free surface lattice Boltzmann
method (FSLBM) for the simulation of bubbly flows including rupture and breakup
of bubbles. The FSLBM uses a volume of fluid approach to reduce the problem of
a liquid-gas two-phase flow to a single-phase free surface simulation. In
bubbly flows compression effects leading to an increase or decrease of pressure
in the suspended bubbles cannot be neglected. Therefore, the free surface
simulation is augmented by a bubble model that supplies the missing information
by tracking the topological changes of the free surface in the flow. The new
model presented here is capable of handling the effects of bubble breakup and
coalesce without causing a significant computational overhead. Thus, the
enhanced bubble model extends the applicability of the FSLBM to a new range of
practically relevant problems, like bubble formation and development in
chemical reactors or foaming processes.
