Rayleigh–Taylor instability

Summary

The Rayleigh–Taylor instability is the instability of the interface between two fluids of different density. It occurs when the heavier fluid lies above the lighter one in a gravity field. More generally it occurs whenever the light fluid pushes or accelerates the heavy one. Small ripples of the interface grow into fingers of heavy fluid falling and bubbles of light fluid rising. It matters in hydrodynamic stability, in inertial confinement fusion, in supernova explosions and in everyday mixing.