Accession Number : AD0706785

Title :   PENETRATION OF A DENSITY DISCONTINUITY BY A TURBULENT VORTEX-PAIR.

Descriptive Note : Technical rept.,

Corporate Author : HYDRONAUTICS INC LAUREL MD

Personal Author(s) : Birkhead,J. L. ; Shwartz,J. ; Tulin,M. P.

Report Date : DEC 1969

Pagination or Media Count : 38

Abstract : 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 pair's 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-pair's density and the square of its velocity, divided by the gravitational acceleration, the density difference of the two fluid layers and the pair's radius, all taken at the point where the pair first impinges on the density discontinuity. (Author)

Descriptors :   (*VORTICES, PENETRATION), THERMAL PROPERTIES, MASS TRANSFER, TURBULENCE, DENSITY, THERMOCLINES, TROPOPAUSE, TWO DIMENSIONAL FLOW, INTERFACES

Subject Categories : Atmospheric Physics
      Physical and Dynamic Oceanography
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE