72th Annual Meeting of the APS Division of Fluid Dynamics (November 23, 2019 — November 26, 2019)

V0058: Marangoni Instability and Interfacial Turbulence; the Story of a Liquor's Birth

Authors

• Sami Yamanidouzisorkhabi, MIT
• Gareth H. McKinley, MIT
• Irmgard Bischofberger, MIT

DOI: https://doi.org/10.1103/APS.DFD.2019.GFM.V0058

Water and ethanol are fully miscible, while anise oil and ethanol are partially miscible and anise oil and water are immiscible. Mixing of all three liquids; however, result in an equilibrium state emulsion of anise microdroplets in water/ethanol solution. Here, we study the mixing of a water drop at the interface of anise oil and ethanol until the equilibrium emulsion state is achieved. We use a combination of regular imaging and Schlieren imaging to visualize the mixing phenomenon. This mixing involves two processes: (i) introduction of a water drop at the anise oil/ethanol interface, Marangoni isntability on the surface of the drop resulting in drop jump, and formation of natural convection caused by exothermic mixing of water and ethanol, (ii) formation of a liquid lens at the interface and its spreading due to Marangoni forces until the equilibrium state is achieved. We show that the inhomogeneities at the anise oil/ethanol interface apply unbalanced Marangoni forces on the vortex ring resulting in its deformation and a non-uniform spreading of the liquid lens, at the interface.