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In fluid thermodynamics, Rayleigh–Bénard convection is a type of natural convection, occurring in a planar horizontal layer of fluid heated from below, in which the fluid develops a regular pattern of convection cells known as Bénard cells.
Convection is caused by yeast releasing CO2. In fluid dynamics, a convection cell is the phenomenon that occurs when density differences exist within a body of liquid or gas. These density differences result in rising and/or falling convection currents, which are the key characteristics of a convection cell. When a volume of fluid is heated, it ...
A fluid under Rayleigh–Bénard convection: the left picture represents the thermal field and the right picture its two-dimensional Fourier transform. Convection, especially Rayleigh–Bénard convection, where the convecting fluid is contained by two rigid horizontal plates, is a convenient example of a pattern-forming system.
In 1913–1914, Bénard and Dauzère made a series of eight films, on convection and solidification in an evaporating fluid, which were produced with the aid of a large firm, the Gaumont studio. [38] Also in these years, the two scientists received subsidies from the Bonaparte Fund, administered by the French Academy of Science, for their research.
Another instance of the Marangoni effect appears in the behavior of convection cells, the so-called Bénard cells. One important application of the Marangoni effect is the use for drying silicon wafers after a wet processing step during the manufacture of integrated circuits. Liquid spots left on the wafer surface can cause oxidation that ...
In fluid mechanics, the Rayleigh number (Ra, after Lord Rayleigh [1]) for a fluid is a dimensionless number associated with buoyancy-driven flow, also known as free (or natural) convection. [ 2 ] [ 3 ] [ 4 ] It characterises the fluid's flow regime: [ 5 ] a value in a certain lower range denotes laminar flow ; a value in a higher range ...
The choice R(u) = u(1 − u) yields Fisher's equation that was originally used to describe the spreading of biological populations, [3] the Newell–Whitehead-Segel equation with R(u) = u(1 − u 2) to describe Rayleigh–Bénard convection, [4] [5] the more general Zeldovich–Frank-Kamenetskii equation with R(u) = u(1 − u)e-β(1-u) and 0 ...
Analyzing the Rayleigh–Bénard convection cell phenomenon, Chandrasekhar (1961) [59] wrote "Instability occurs at the minimum temperature gradient at which a balance can be maintained between the kinetic energy dissipated by viscosity and the internal energy released by the buoyancy force." With a temperature gradient greater than the minimum ...