Kelvin-Helmholtz instability - 3D cross section view
Kelvin-Helmholtz simulation performed using my lattice Boltzmann GPU code (Nvidia CUDA). This simulation uses 1 billion cells, Reynolds number of around 9000 and Richardson number of .
This type of flow occurs when a light fluid is flowing over a heavy fluid and the shear at the interface causes waves eventually leading to an instability. You can see this type of flow in nature, for eg. clouds or even the surface of Jupiter!