Bubble ribbons under imposed flow

Bubble rafts consisting of a single layer of bubbles floating on the surface of water have proven to be an important model system for studying materials ranging from crystalline systems to amorphous solids to complex fluids. An interesting question in foams and complex fluids is how the detailed nature of the bubble-bubble interactions determines the resulting stable states of the system, especially in the context of different approaches to generating the foam or complex fluid. In this paper, we report on the generation of bubble rafts using an imposed flow. The flow breaks the symmetry of the system and allows for the generation of stable bubble ribbons of many different widths. We report on the transition between ribbons of different widths and the ultimate separation of the system into multiple small ribbons. An interesting feature of the system is the stability of very narrow ribbons against self-folding. In principle, folding of the ribbons would produce states with lower global energy. Therefore, understanding the energy barriers and dynamics involved in the prevention of this transition will play a role in deepening our understanding of these systems.