Natural convection

Summary

Natural convection, also called free convection, is convective heat transfer in which the fluid moves only because of buoyancy. Temperature differences make the density of the fluid uneven, and gravity then lifts the lighter parts and sinks the heavier ones. It cools electronics without fans, heats rooms from radiators, and drives flows in the atmosphere, the oceans and the Earth's mantle. The heating of a fluid layer from below, Rayleigh–Bénard convection, is its model problem.