Rayleigh-Bènard convection

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Rayleigh-Bènard convection

[′rā·lē bā′när kən‚vek·shən]
(physics)
Convection of a fluid heated from below, characterized by a regular array of usually hexagonal cells.
References in periodicals archive ?
These are called Benard cells. They tend to be hexagonal in shape, but may be four- or five-sided or even roughly circular.
Early forms of such organization can be found in the astonishing ability of dissipative structures such as Benard cells to maintain extremely improbable configurations under far from equilibrium conditions.
A classic simple example of emergence is the formation of Benard cells as water is heated in a pan.
This creates a successive cell that is well known as Benard cells. It is important to note that the Rayleigh number in the present study is based on the total height of the enclosure.
On the surface structure and the hydrodynamics of the Benard Cells. Experiment.
Visibly, Benard cells of a given medium are very similar to each other, as well as the subsequent cycles of the Belousov-Zhabotinsky (BZ) reaction.
(2) Flow currents within the film (9-10) -- In the wet film, as water volatilizes, the temperature, surface, and interfacial tension will decline, more hydrophilic pigments will be carried with water to the surface, and Benard cells are formed.
It prevents adequate flow-out and leveling (the resultant surface may be quite rough and/or bumpy), often produces streaks and blotches, prevents good color development, causes flooding, floating and Benard cells, and generally hurts appearance.
Flocculation can contribute to a number of defects, including poor gloss, poor leveling, flooding and floating, Benard cells, and poor color development (see the March 2006 issue of JCT COATINGSTECH for more information on flocculation).
It prevents adequate flow-out and leveling (the surface may be quite rough), often produces streaks and blotches, prevents good color development, causes flooding, floating and Benard cells, and generally hurts appearance.
Haze may be due to fine solvent pops or pinholes, fine orange peel, roughness (caused by dry spray, flocculation or poor coalescence), small Benard cells, material that has exuded to the surface, material that condensed on the surface in the oven, absorption or trapping of moisture (which may be a form of blushing), degradation by overbaking, or the effects of oven gasses on the surface.
Benard cells are defects that look as if someone has imprinted a series of hexagonal shapes on the surface of the paint film.