Same as for the 2D case, two immiscible fluids are simulated, implemented through the Shan-Chen model. The red fluid is initially located in a layer on top of the blue fluid, and feels the action of gravity. As a way of modeling a large density difference between the fluids, the blue fluid is assumed to be unaware of gravity. After some time, a Rayleigh-Taylor instability occurs, and the red fluid penetrates the blue one. The size of the simulation is 400x400x400.

3D Rayleigh-Taylor instability