Journal ArticleDOI
Natural convection above unconfined horizontal surfaces
Zeev Rotem,Lutz Claassen +1 more
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In this paper, the existence of a laminar boundary layer above a horizontal plate at intermediate Grashof (respectively Rayleigh) numbers, and its extent along the plate, was demonstrated experimentally using semi-focusing colour-Schlieren photography.Abstract:
The paper discusses free convective flows above a horizontal plate, both theoretically and on the basis of experiments which yield quantitative data. The theory is applicable to the semi-infinite plate and is extended to cover the complete range of Prandtl number values including Pr → 0 and Pr → ∞. Experiments were carried out to demonstrate the existence of a laminar boundary layer above a horizontal plate at intermediate Grashof (respectively Rayleigh) numbers, and its extent along the plate. This layer breaks down into large-eddy instability some distance from the leading edge. The value of the critical Rayleigh number for this to occur, obtained experimentally using semi-focusing colour-Schlieren photography is in reasonable qualitative agreement with previously known data (Tritton 1963a,b).read more
Citations
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New perspectives in turbulent Rayleigh-Bénard convection.
Francesca Chillà,Jörg Schumacher +1 more
TL;DR: Key emphasis is given to the physics and structure of the thermal and velocity boundary layers which play a key role for the better understanding of the turbulent transport of heat and momentum in convection at high and very high Rayleigh numbers.
Journal ArticleDOI
Natural convection mass transfer adjacent to horizontal plates
TL;DR: In this article, the authors used the naphthalene sublimation technique to perform mass transfer at a heated isothermal upwardfacing plate or at a cooled downward-facing plate.
Journal ArticleDOI
Buoyancy induced flows in a saturated porous medium adjacent to impermeable horizontal surfaces
Cheng Ping,Chang I-Dee +1 more
TL;DR: In this paper, boundary-layer analysis for buoyancy-induced flows in a saturated porous medium adjacent to horizontal impermeable surfaces is performed for the convective flow above a heated surface or below a cooled surface, where wall temperature is a power function of distance from the origin.
Journal ArticleDOI
Natural convection boundary layer flow over horizontal and slightly inclined surfaces
L Pera,Benjamin Gebhart +1 more
TL;DR: In this article, the effect of small surface inclination on flow and transport is studied as a perturbation of flow over a horizontal surface, and the temperature distributions and heat transfer parameters were measured for the first time in such a flow, in air at atmospheric pressure.
Journal ArticleDOI
Boundary layer structure in turbulent Rayleigh-Bénard convection
TL;DR: In this article, the structure of the boundary layers in turbulent Rayleigh-B´ enard convection is studied by means of three-dimensional direct numerical simulations, and the results demonstrate that important assumptions of existing classical laminar boundary layer theories for forced and natural convection are violated, such as the strict two-dimensionalality of the dynamics or the steadiness of the fluid motion.
References
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An analysis of laminar free-convection flow and heat transfer about a flat plate parallel to the direction of the generating body force
TL;DR: In this article, the free-convection flow and heat transfer about a flat plate parallel to the direction of the body force are formally analyzed and the type of flow is found to be dependent on the Grashof number alone.
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On the free convection from a horizontal plate
TL;DR: In this paper, a freie Konvektion an einer beheizten horizontalen Platte wird nach den ublichen Methoden der Grenzschichttheorie untersucht, wohl aber findet man eine widerspruchsfreie Losung, wenn diese Plattenseite nach unten weist.
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Free convection on a horizontal plate
TL;DR: In this paper, Stewartson concerne les conditions d'existence des couches limites resultant de convection libre dans le cas d'une plaque plane horizontalale.
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Transition to turbulence in the free convection boundary layers on an inclined heated plate
TL;DR: In this article, an experimental study has been made of transition to turbulence in the free convective flows on a heated plate, with the plate vertical and inclined at angles up to about 50° to the vertical, both above and below the plate.