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Experimental investigation of convective stability in a superposed fluid and porous layer when heated from belowExperiments have been carried out in a horizontal superposed fluid and porous layer contained in a test box 24 cm x 12 cm x 4 cm high. The porous layer consisted of 3 mm diameter glass beads, and the fluids used were water, 60 and 90 percent glycerin-water solutions, and 100 percent glycerin. The depth ratio d, which is the ratio of the thickness of the fluid layer to that of the porous layer, varied from 0 to 1.0. Fluids of increasingly higher viscosity were used for cases with larger d in order to keep the temperature difference across the tank within reasonable limits. The size of the convection cells was inferred from temperature measurements made with embedded thermocouples and from temperature distributions at the top of the layer by use of liquid crystal film. The experimental results showed: (1) a precipitous decrease in the critical Rayleigh number as the depth of the fluid layer was increased from zero, and (2) an eightfold decrease in the critical wavelength between d = 0.1 and 0.2. Both of these results were predicted by the linear stability theory reported earlier (Chen and Chen, 1988).
Document ID
19900028892
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Chen, Falin
(Arizona Univ. Tucson, AZ, United States)
Chen, C. F.
(Arizona, University Tucson, United States)
Date Acquired
August 14, 2013
Publication Date
October 1, 1989
Publication Information
Publication: Journal of Fluid Mechanics
Volume: 207
ISSN: 0022-1120
Subject Category
Fluid Mechanics And Heat Transfer
Accession Number
90A15947
Funding Number(s)
CONTRACT_GRANT: NSF MSM-87-02732
CONTRACT_GRANT: NAG3-723
Distribution Limits
Public
Copyright
Other

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