Kelvin-Helmholtz Instability

Kelvin-Helmholtz instability on Saturn, formed by the interaction of two layers of the atmosphere

Numerical simulation of the Kelvin-Helmholtz time instability

The Kelvin – Helmholtz instability arises when there is a shift between the layers of a continuous medium , or when the two contacting media have a sufficient velocity difference. At the same time, in the section perpendicular to the interface of these media, the velocity profile has an inflection point (the second velocity derivative with respect to the section coordinate vanishes). As Rayleigh showed , the current with the presence in the velocity profile of the inflection point is unstable. A typical example of such instability is the occurrence of waves on the surface of water under the action of wind. Another example is the atmosphere perturbation on Jupiter.