How droplets go from ‘donut’ to sphere

New research clarifies how toroidal droplets—which initially take the shape of a donut—evolve into spherical droplets by collapsing into themselves or breaking up into smaller droplets. Work with droplets has implications for the life sciences, and could improve industrial processes....“Surface tension drives the evolution of the droplets,” says Alexandros Fragkopoulos, a PhD candidate at Georgia Institute of Technology. “Fluids tend to minimize their surface area for a given volume because that minimizes the energy required to have an interface between different fluids. Spherical shapes minimize that energy, and as a result, toroidal droplets want to evolve to become spherical. We’re studying how that transition occurs."...The impetus for the experimental work was inconsistencies between theoretical predictions and computer simulation of toroidal droplet transitions. What the researchers found tends to back up the simulation results. “However, the earlier theoretical work was essential in guiding the theory efforts and in illustrating what the problem was in order to correctly describe the experimental results,” says Alberto Fernandez-Nieves, in whose lab the research took place. Alexandros Fragkopoulos is a graduate teaching assistant in the School of Physics, where Alberto Fernandez-Nieves is an associate professor.