Gravity currents in the laboratory, atmosphere, and ocean

Analytic models for the behavior of gravity currents are discussed, along with observed displays of the presence of the effect. A current flowing along a horizontal surface is noted to have a foremost point raised slightly above the ground, and is modified by the interaction with ambient conditions.The interface of two fluids at the head of a gravity current is noted to be a frontal zone, where a high density gradient is observed. Consideration is given to the application of inviscid-fluid theory to steady gravity currents, and to the spread of negatively buoyant fluids. Specific instances of gravity currents are outlined as occurring in the atmosphere, in the ocean, and in cases of ambient stratification, and it is noted that gravity currents have been detected on two other planets.