| definition |
- Convection is energy transfer through motion of within the fluid resulting in transport and mixing of the properties of the fluid. In oceanography, convection plays a role in the transfer of heat away from the ocean. As the air near the warm sea surface gets heated, it expands and rises, carrying the heat away. In physical oceanography, the sinking of surface waters to form deep water masses, a process of fundamental importance for ocean climate and the maintenance of a stably stratified world ocean. There are two main types of deep convection, the physics of which are very different. The first is convection near an open boundary,
which involves the formation of a dense water mass which reaches the bottom of the ocean by descending a continental slope. The second type is open-ocean deep convection, where the sinking occurs far from land and is predominantly vertical.
|
| Abstract from DBPedia | Convection is single or multiphase fluid flow that occurs spontaneously due to the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When the cause of the convection is unspecified, convection due to the effects of thermal expansion and buoyancy can be assumed. Convection may also take place in soft solids or mixtures where particles can flow. Convective flow may be transient (such as when a multiphase mixture of oil and water separates) or steady state (see Convection cell). The convection may be due to gravitational, electromagnetic or fictitious body forces. Heat transfer by 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 identified by clouds, with stronger convection resulting in thunderstorms. Natural convection also plays a role in stellar physics. Convection is often categorised or described by the main effect causing the convective flow, e.g. Thermal convection. Convection cannot take place in most solids because neither bulk current flows nor significant diffusion of matter can take place. Granular convection is a similar phenomenon in granular material instead of fluids.Advection is fluid motion created by velocity instead of thermal gradients.Convective heat transfer is the intentional use of convection as a method for heat transfer.対流（たいりゅう、英語: convection）とは、流体において温度や表面張力などが原因により不均質性が生ずるため、その内部で重力によって引き起こされる流動が生ずる現象である。 地球の大気においては、大気の鉛直方向の運動は高度 0 キロメートルから約 11 キロメートルの層に限られ、この領域を対流圏と呼ぶ。また地球や惑星の内部では、対流により内部の熱源から地表面への熱輸送が生じており、地表面の変動を引き起こす原因となっている。 近年、計算機の性能が向上し、流体の運動方程式（ナビエ-ストークスの式）を高精度に計算することが可能となったため、コンピュータを用いたシミュレーションによる対流現象の研究が盛んに行われており、工学的な技術としても重要な分野である。また惑星内部の対流など、実験・観測が不可能な領域における流体の挙動を理論的に解明する研究も行われている。 (Source: http://dbpedia.org/resource/Convection) |
