Convection

Convection is the concerted, collective movement of ensembles of molecules within fluids (e.g., liquids, gases) and rheids. Convection of mass cannot take place in solids, since neither bulk current flows nor significant diffusion can take place in solids. Diffusion of heat can take place in solids, but is referred to separately in that case as heat conduction. A good model for convection is when you take a heat source (e.g. Bunsen burner) and place it at any side of a glass full of a liquid, you then can feel the different levels of heat in the glass.

Convective heat transfer is one of the major modes of heat transfer and convection is also a major mode of mass transfer in fluids. Convective heat and mass transfer take place through both diffusion – the random Brownian motion of individual particles in the fluid – and by advection, in which matter or heat is transported by the larger-scale motion of currents in the fluid. In the context of heat and mass transfer, the term "convection" is used to refer to the sum of advective and diffusive transfer. Note that in common use the term convection may refer loosely to heat transfer by convection, as opposed to mass transfer by convection, or the convection process in general. Sometimes "convection" is even used to refer specifically to "free heat convection" (natural heat convection), as opposed to forced heat convection. However, in mechanics the correct use of the word is the general sense, and different types of convection should be properly qualified for clarity.

Convection can be qualified in terms of being natural, forced, gravitational, granular, or thermomagnetic. It may also be said to be due to combustion, capillary action, or Marangoni and Weissenberg effects. Due to its role in heat transfer, natural convection plays a role in the structure of Earth's atmosphere, its oceans, and its mantle. Discrete convective cells in the atmosphere can be seen as clouds, with stronger convection resulting in thunderstorms. Natural convection also plays a role in stellar physics.

Read more about Convection:  Terminology, Examples and Applications of Convection, Convection Mechanisms, Mathematical Models of Convection

Other articles related to "convection":

Meteorological History Of Hurricane Jeanne - Second Landfall and Reorganization
... its eye feature and well-defined inner core of convection ... storm status, and by 24 hours after landfall its convection had deteriorated as the eye feature dissipated ... depression, the original center of circulation tracked westward away from the convection and dissipated ...
Convection–diffusion Equation
... The convection–diffusion equation is a combination of the diffusion and convection (advection) equations, and describes physical phenomena where particles, energy, or ...
Atmospheric Convection
... Atmospheric convection is the result of a parcel-environment instability, or temperature difference, layer in the atmosphere ... Moist convection leads to thunderstorm development, which is often responsible for severe weather throughout the world ...
Mathematical Models of Convection - Quantifying Natural Versus Forced Convection
... In cases of mixed convection (natural and forced occurring together) one would often like to know how much of the convection is due to external constraints, such as ... The relative magnitudes of the Grashof and Reynolds number squared determine which form of convection dominates ... if forced convection may be neglected, whereas if natural convection may be neglected ...
Tropical Depression Five-E (2008) - Meteorological History
... tropical wave, associated with scattered convection, which formed off the coast of Africa on June 23 ... Some cyclonic turning was noted and convection was on either side of the axis— the center of the storm—but was mainly in association with the Intertropical Convergence Zone (ITCZ) ... On July 2, the wave moved over Central America and produced scattered areas of strong convection off the coast of Honduras ...