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In continuum mechanics, the Péclet number (Pe, after Jean Claude Eugène Péclet) is a class of dimensionless numbers relevant in the study of transport phenomena in a continuum. It is defined to be the ratio of the rate of advection of a physical quantity by the flow to the rate of diffusion of the same quantity driven by an appropriate ...
Dimensionless numbers (or characteristic numbers) have an important role in analyzing the behavior of fluids and their flow as well as in other transport phenomena. [1] They include the Reynolds and the Mach numbers, which describe as ratios the relative magnitude of fluid and physical system characteristics, such as density, viscosity, speed of sound, and flow speed.
Small values of the Prandtl number, Pr ≪ 1, means the thermal diffusivity dominates. Whereas with large values, Pr ≫ 1, the momentum diffusivity dominates the behavior. For example, the listed value for liquid mercury indicates that the heat conduction is more significant compared to convection, so thermal diffusivity is dominant. However ...
Peclet number is defined to be the ratio of the rate of convection of a physical quantity by the flow to the rate of diffusion of the same quantity driven by an appropriate gradient. The variation between ϕ {\displaystyle \phi \,} and x is depicted in Figure for a range of values of the Peclet number.
is a typical velocity of the flow, is a typical length scale of the flow, is the magnetic diffusivity. The mechanism by which the motion of a conducting fluid generates a magnetic field is the subject of dynamo theory. When the magnetic Reynolds number is very large, however, diffusion and the dynamo are less of a concern, and in this case ...
Measured values span several orders of magnitude. Of all fluids, gases have the lowest viscosities, and thick liquids have the highest. The values listed in this article are representative estimates only, as they do not account for measurement uncertainties, variability in material definitions, or non-Newtonian behavior.
Is it worth saying that values of the Peclet number are typically very large in most engineering applications? 128.12.20.32 21:49, 21 February 2006 (UTC) []. Absolutely. I think that is a useful piece of information and I have added it to the article.
The number is named after Italian scientist Carlo Marangoni, although its use dates from the 1950s [1] [2] and it was neither discovered nor used by Carlo Marangoni. The Marangoni number for a simple liquid of viscosity μ {\displaystyle \mu } with a surface tension change Δ γ {\displaystyle \Delta \gamma } over a distance L {\displaystyle L ...