2013/12/23 by José Federico Hernández-Sánchez, Hernández-Sánchez, José Federico, Antonin Eddi +3
Physics and Astronomy · #FOS: Physical sciences #Fluid Dynamics (physics.flu-dyn) #physics.flu-dyn
paper · pdf · doi:10.48550/arxiv.1312.6590
10 pages, 5 figures
arxiv created 2013/12/23 · arxiv updated 2013/12/24
Bringing the interfaces of two miscible fluids into contact naturally generates strong gradients in surface tension. Here we investigate such a Marangoni-driven flow by continuously supplying isopropyl alcohol (IPA) on a film of water, using micron-sized droplets of IPA-water mixtures. These droplets create a localized depression in surface tension that leads to the opening of a circular and thin region in the water film. At the edge of the thin region, there is a rim growing and collecting the water of the film. We find that the spreading radius scales as r ∼ t1/2. This result can be explained from a balance between Marangoni and viscous stresses, assuming that the gradients in surface tension are smoothened out over the entire size of the circular opening. We derive a scaling law that accurately predicts the influence of the IPA flux as well as the thickness of the thin film at the interior of the spreading front.