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Convection, especially Rayleigh–Bénard convection, where the convecting fluid is contained by two rigid horizontal plates, is a convenient example of a pattern-forming system. When heat is fed into the system from one direction (usually below), at small values it merely diffuses ( conducts ) from below upward, without causing fluid flow.
In fluid dynamics, a convection cell is the phenomenon that occurs when density differences exist within a body of liquid or gas. These density differences result in rising and/or falling convection currents, which are the key characteristics of a convection cell. When a volume of fluid is heated, it expands and becomes less dense and thus more ...
A hot, less-dense material at the bottom moves upwards, and likewise, cold material from the top moves downwards. Convection (or convective heat transfer) is the transfer of heat from one place to another due to the movement of fluid. Although often discussed as a distinct method of heat transfer, convective heat transfer involves the combined ...
A hot, less-dense lower boundary layer sends plumes of hot material upwards, and cold material from the top moves downwards. Heat transfer is a discipline of thermal engineering that concerns the generation, use, conversion, and exchange of thermal energy (heat) between physical systems. Heat transfer is classified into various mechanisms, such ...
Newton's law of cooling. In the study of heat transfer, Newton's law of cooling is a physical law which states that the rate of heat loss of a body is directly proportional to the difference in the temperatures between the body and its environment. The law is frequently qualified to include the condition that the temperature difference is small ...
Atmospheric convection is called "deep" when it extends from near the surface to above the 500 hPa level, generally stopping at the tropopause at around 200 hPa. [citation needed] Most atmospheric deep convection occurs in the tropics as the rising branch of the Hadley circulation and represents a strong local coupling between the surface and ...
Thermal conduction (power) is the heat per unit time transferred some distance ℓ between the two temperatures. κ is the thermal conductivity of the material. A is the cross-sectional area of the object. ΔT is the difference in temperature from one side to the other. ℓ is the length of the path the heat has to be transferred.
The first case is when natural convection aids forced convection. This is seen when the buoyant motion is in the same direction as the forced motion, thus accelerating the boundary layer and enhancing the heat transfer. [5] Transition to turbulence, however, can be delayed. [6] An example of this would be a fan blowing upward on a hot plate.