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Plume Impingement
In hydrodynamics, a plume or a column is a vertical body of one fluid moving through another. Several effects control the motion of the fluid, including momentum (inertia), diffusion and buoyancy (density differences). Pure ''jets'' and pure ''plumes'' define flows that are driven entirely by momentum and buoyancy effects, respectively. Flows between these two limits are usually described as forced plumes or buoyant jets. "Buoyancy is defined as being positive" when, in the absence of other forces or initial motion, the entering fluid would tend to rise. Situations where the density of the plume fluid is greater than its surroundings (i.e. in still conditions, its natural tendency would be to sink), but the flow has sufficient initial momentum to carry it some distance vertically, are described as being negatively buoyant. Movement Usually, as a plume moves away from its source, it widens because of entrainment of the surrounding fluid at its edges. Plume shapes can be influen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Defense
Defense or defence may refer to: Tactical, martial, and political acts or groups * Defense (military), forces primarily intended for warfare * Civil defense, the organizing of civilians to deal with emergencies or enemy attacks * Defense industry, industry which manufactures and sells weapons and military technology * Self-defense, the use of force to defend oneself * Haganah (Hebrew for "The Defence"), a paramilitary organization in British Palestine * National security, security of a nation state, its citizens, economy, and institutions, as a duty of government ** Defence diplomacy, pursuit of foreign policy objectives through the peaceful employment of defence resources ** Ministry of defence or department of defense, a part of government which regulates the armed forces ** Defence minister, a cabinet position in charge of a ministry of defense * International security, measures taken by states and international organizations to ensure mutual survival and safety Sports * Def ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |