PENETRATION OF A DENSITY DISCONTINUITY BY A TURBULENT VORTEX-PAIR.
HYDRONAUTICS INC LAUREL MD
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Studies were carried out concerning the penetration of an isolated, rising fluid mass through a density discontinuity, such as may exist in the atmosphere the tropopause and in the oceans the thermoclines. The rising mass was two-dimensional, turbulent, and had the characteristic shape and internal motions of a vortex-pair, or thermal. An analysis of the pairs motion through a density discontinuity, based on the conservation laws for volume, buoyancy and energy, reveals that the maximum rise of the vortex-pair above the density interface is proportional to the square root of its characteristic densometric Froude number. Model experiments, carried out in a stratified, two-layer, saline-water tank, with thermals impinging on the density interface, have clearly confirmed this conclusion. The densometric Froude number is defined in this case as the product of the vortex-pairs density and the square of its velocity, divided by the gravitational acceleration, the density difference of the two fluid layers and the pairs radius, all taken at the point where the pair first impinges on the density discontinuity. Author
- Atmospheric Physics
- Physical and Dynamic Oceanography
- Fluid Mechanics