Convection

Uncommon card · No. 120524

Convection is the movement of a fluid caused by differences in its properties, especially density, acting together with body forces. In fluid mechanics, the term has this broad meaning, while in thermodynamics it is often used specifically for heat transfer by convection. The most familiar example is natural convection, in which buoyancy causes less-dense fluid to rise and denser fluid to sink. Differences in temperature or composition can produce the required density contrasts, although other forces can also drive convection, as in thermomagnetic convection. Convection is common in the atmosphere and oceans and also occurs in Earth's mantle, in stars, and in some solid materials such as ice. It is important in practical systems including ventilation, cooling, and nuclear reactors. Convective motion can also organize itself into convection cells and other recurring patterns; Rayleigh–Bénard convection is a well-known example. Whether natural convection develops depends on the relative effects...

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