Simplified modeling of the influence of surfactants on the rise of bubbles in VOF-simulations

A momentum jump condition is derived which models the influence of surface active agents at fluid interfaces due to Marangoni stresses. Underlying assumptions are quasi-stationary shape and surfactant distribution. The model is simple to implement into sharp interface two-phase flow solvers and VOF-based numerical simulations show that the effect of the jump condition is comparable to stagnant cap type models for small bubbles. An explicit cap angle is not needed, making it applicable to non-symmetric interface geometries, where a cap angle is hard to define. This approach via a modified interfacial momentum jump condition is also suitable for Front tracking or Level Set methods.