Type of Document	Dissertation
Author	Fernandes, Alexandre Macedo
Author's Email Address	alexmf@gfdi.fsu.edu
URN	etd-11272006-155034
Title	Salt Finger Fluxes in a Laminar Shear Flow
Degree	Doctor of Philosophy
Department	Oceanography, Department of
Advisory Committee	Advisor Name Title Georges Weatherly Committee Member Krishnamurti T.N Committee Member Louis St. Laurent Committee Member Ruby Krishmaurti Committee Member Thorsten Dittmar Committee Member
Keywords	Convection Instability Analysis Double-Diffusion Navier Stokes Equations Cylindrical Coordinates Particle Image Velocimetry
Date of Defense	2006-11-07
Availability	unrestricted
Abstract This dissertation presents an experimental study of the buoyancy fluxes produced by salt fingers in the presence of a laminar shear flow. An annular tank was used in the experiments. Sugar and salt were used as the diffusing components. Salt fingers, initially aligned in the vertical, were observed to tilt when the shear flow was imposed. The fingers were also observed to be 3-dimensional structures at all times during the experiments. A consistent decrease in the salt fluxes was measured as the the Reynolds number was increase by increasing the shear velocity magnitudes. Through a regression analysis, the salt fluxes were found to depend upon the Reynolds number as powers given by -0.025, -0.1 and -0.34, when the density ratio was equal to 1.2, 1.54 and 2.1 respectively. A polynomial expression that encompasses the dependence of the salt fluxes with Reynolds number and density ratio is also suggested. A linear stability theory for fingers tilted by a shear flow together with a flux reduction mechanism, proposed by Krishnamurti (personal communication), are suggested as possible explanations for the experimental results.
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