Paper detail

Symmetry breaking and chaos in evaporation driven Marangoni flows over bubbles

Understanding the dynamics of liquid films that make up bubbles is of practical and fundamental importance. Practically, this understanding is crucial for tuning bubble stability, while fundamentally, thin films are an excellent platform to study 2D flows. Here we study the spatiotemporal film thickness dynamics of bubbles subjected to evaporation driven Marangoni flows. Initially, we demonstrate how bubble stability can be dramatically tuned with the help of evaporation driven flows. Subsequently, we reveal that the spatial symmetry of thickness profiles evolves non-monotonically with the volatile species concentration, with profiles being axisymmetric at the two extremes in concentration. At $50\%$ concentration, spatial symmetry breaks down and thickness fluctuations are chaotic everywhere in space, with the fluctuation statistics becoming spatially invariant and ergodic. For these cases, the power spectrum of thickness fluctuations follow the Kolmogorov $-5/3$ scaling - a first such demonstration for forcing by evaporation. These results along with the reported setup provide an excellent framework to further investigate 2D chaotic flows.