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- In fluid dynamics, a gravity current or density current is a primarily horizontal flow in a gravitational field that is driven by a density difference in a fluid or fluids and is constrained to flow horizontally by, for instance, a ceiling. Typically, the density difference is small enough for the Boussinesq approximation to be valid. Gravity currents can be thought of as either finite in volume, such as the pyroclastic flow from a volcano eruption, or continuously supplied from a source, such as warm air leaving the open doorway of a house in winter. Other examples include dust storms, turbidity currents, avalanches, discharge from wastewater or industrial processes into rivers, or river discharge into the ocean. Gravity currents are typically much longer than they are tall. Flows that are primarily vertical are known as plumes. As a result, it can be shown (using dimensional analysis) that vertical velocities are generally much smaller than horizontal velocities in the current; the pressure distribution is thus approximately hydrostatic, apart from near the leading edge. Gravity currents may be simulated by the shallow water equations, with special dispensation for the leading edge which behaves as a discontinuity. When a gravity current propagates along a plane of neutral buoyancy within a stratified ambient fluid, it is known as a gravity current intrusion. (en)
- 密度流（みつどりゅう）とは水平方向の流体の密度偏差に起因する圧力勾配によって駆動される流れ。 (ja)
- 海水密度受水溫和鹽度的影響，不同密度的海水相接觸時，密度大的海水壓力較大，因此會流向密度小的區域。這種因密度分布不均產生的壓力差而造成海水流動，就稱為密度流，降水及河流流入都會降低海水密度，而海面水蒸發則會升高海水密度。 (zh)
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- 密度流（みつどりゅう）とは水平方向の流体の密度偏差に起因する圧力勾配によって駆動される流れ。 (ja)
- 海水密度受水溫和鹽度的影響，不同密度的海水相接觸時，密度大的海水壓力較大，因此會流向密度小的區域。這種因密度分布不均產生的壓力差而造成海水流動，就稱為密度流，降水及河流流入都會降低海水密度，而海面水蒸發則會升高海水密度。 (zh)
- In fluid dynamics, a gravity current or density current is a primarily horizontal flow in a gravitational field that is driven by a density difference in a fluid or fluids and is constrained to flow horizontally by, for instance, a ceiling. Typically, the density difference is small enough for the Boussinesq approximation to be valid. Gravity currents can be thought of as either finite in volume, such as the pyroclastic flow from a volcano eruption, or continuously supplied from a source, such as warm air leaving the open doorway of a house in winter. Other examples include dust storms, turbidity currents, avalanches, discharge from wastewater or industrial processes into rivers, or river discharge into the ocean. (en)
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- Gravity current (en)
- 密度流 (ja)
- 密度流 (zh)
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