  Surfactant transport plays an important role in many technical processes and
industrial applications such as chemical reactors, microfluidics, printing and
coating technology. High fidelity numerical simulations of two-phase flow
phenomena reveal rich insights into the flow dynamics, heat, mass and species
transport. In the present study, a two-field formulation for surfactant
transport within the algebraic volume of fluid method is presented. The slight
diffuse nature of representing the interface in the algebraic volume of fluid
method is utilized to track the concentration of surfactant at the interface as
a volumetric concentration. Transport of insoluble and soluble surfactants is
investigated by tracking two different concentrations of the surfactant, one
within the bulk of the liquid and the other one at the interface. These two
transport equations are in turn coupled by source terms considering the
ad-/desorption processes at a liquid-gas interface. Appropriate boundary
conditions at a solid-fluid interface are formulated to ensure surfactant
conservation, while also enabling to study the ad-/desorption processes at a
solid-fluid interface. The developed numerical method is verified by comparing
the numerical simulations with well-known analytical and numerical reference
solutions. The presented numerical methodology offers a seamless integration of
surfactant transport into the algebraic volume of fluid method, where the
latter has many advantages such as volume conservation and an inherent ability
of handling large interface deformations and topological changes.
