What happens when you drop a volume of water in a container filled with a layer of oil? Well, you could perform an experiment… but we decided to simulate it instead.
We used the new modular solver ‘multiphaseEuler’ from OpenFOAM 11 to simulate 3 segregated phases: water, oil and air. The first two phases are considered to be incompressible, whereas we use the perfect gas law for air. All 3 phases are considered isothermal. The 3 possible interface types between these phases have their own surface or interfacial tension.
What you see in the movie is that when the water hits the oil layer, air is also entrained into the oil. The air bubbles rise to the surface, whereas the water moves to the bottom of the container.