Análisis de la influencia de surfactantes, viscoelasticidad y campos eléctricos en la rotura de superficies libres

Abstract

The breakup of interfaces constitutes a fascinating problem due to its singular behavior and the dependency of length scale with time. In the pinch-off, the velocity diverges, reaching extraordinarily small scales, which adopts a universal behavior. We analyze experimentally the breakup of interfaces using high-speed imaging. We examine the influence of three factors: a surfactant monolayer, viscoelasticity, and the action of an axial electric field. Both experiments and numerical simulations allow us to determine the deviation of the system evolution from that of the reference system, i.e., a clean Newtonian fluid in the absence of electric fields. In addition, the breakup of a surfactant-covered droplet submerged in an extensional flow is studied numerically. The results obtained in this thesis shed light on the forces dominating the finite-time singularity approached by the system next to the pinch-off point and enable us to validate the theoretical models under these singular conditions.