More recently, numerical methods were applied to identify the shape of such droplets. In these instances, the liquid droplet is less dense than the supporting liquid, and gravity always plays a stabilizing role on the system.
In this work a numerical model was developed from the Young−Laplace equation on three interfaces (water/oil, water/air, and oil/air) to predict the theoretical equilibration conditions. The model was verified successfully with an oil/water system. The stability of the floating droplet depends on the combination of three interface tensions, oil density, and water droplet volume. For practical purposes, however, the equilibrium contact angle has to be greater than 5° so the water droplet can effectively float. This result has significant applications for biodegrading oil wastes.
Can Water Float on Oil?
Chi M. Phan,* Benjamin Allen, Luke B. Peters, Thu N. Le, and Moses O. Tade
Department of Chemical Engineering, Curtin University, GPO Box U1987, Perth WA 6845, Australia
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