Rayleigh–Bénard convection

Summary

Rayleigh–Bénard convection is the motion of a horizontal layer of fluid heated from below and cooled from above. When the temperature difference is small, heat crosses the layer by conduction and the fluid stays at rest. When the Rayleigh number exceeds a critical value, the rest state becomes unstable and the fluid organises into convection rolls or cells. It is the standard model problem for buoyancy-driven hydrodynamic stability, pattern formation and thermal turbulence.