“Froude number”的概念、定义、翻译、参考文献-科学参考

Froude number

Chemical Engineering

A widely used dimensionless number, Fr, that represents the influence of gravity in the power relationship for fluid systems such as pumping, mixing in unbaffled tanks and reactors, and in determining the extent of fluidization of particles in a fluidized bed. For a fluidized bed it is expressed as:
$F r = \frac{v^{2} d_{p}}{g}$

where v is the minimum fluid velocity calculated over the entire cross-section of the bed, d_p is the particle diameter (or diameter corresponding to the surface mean diameter), and g is the gravitational acceleration. Since the viscosity of gases is low, the velocity is high and aggregative fluidization occurs for Fr greater than a value of 1. Particulate fluidization occurs for Fr less than 1. For stirred tanks it is expressed as:
$F r = \frac{N^{2} D}{g}$

where D is the diameter of the impeller and N is the rotational speed in rps. It is named after British engineer William Froude (1810–79) who developed laws for the resistance of the hulls of ships in water and in predicting their stability.

Geology and Earth Sciences

A dimensionless number equal to the ratio of water velocity to the speed of a gravity wave, used to assess whether flow in an open channel is critical, tranquil, or shooting. If the Froude number is less than 1, flow is said to be subcritical or slow; if Fr = 1, flow is critical; and if Fr is greater than 1, flow is fast or supercritical.

Geography

The ratio of the velocity (v) of a river to its celerity where celerity is the product of the acceleration due to gravity (g) and the mean depth of flow (d). The Froude number (Fe) is calculated from the equation:
$F_{e} = \frac{v}{\sqrt{g d}}$
Where F_e is less than 1, deeper flow is tranquil. Where F_e exceeds 1, the flow is turbulent. See Lewin and Brewer (2001) Geomorph. 40 on Froude numbers and channel patterns.

单词	Froude number
释义	Froude number Chemical Engineering A widely used dimensionless number, Fr, that represents the influence of gravity in the power relationship for fluid systems such as pumping, mixing in unbaffled tanks and reactors, and in determining the extent of fluidization of particles in a fluidized bed. For a fluidized bed it is expressed as: $F r = \frac{v^{2} d_{p}}{g}$ where v is the minimum fluid velocity calculated over the entire cross-section of the bed, d_p is the particle diameter (or diameter corresponding to the surface mean diameter), and g is the gravitational acceleration. Since the viscosity of gases is low, the velocity is high and aggregative fluidization occurs for Fr greater than a value of 1. Particulate fluidization occurs for Fr less than 1. For stirred tanks it is expressed as: $F r = \frac{N^{2} D}{g}$ where D is the diameter of the impeller and N is the rotational speed in rps. It is named after British engineer William Froude (1810–79) who developed laws for the resistance of the hulls of ships in water and in predicting their stability. Geology and Earth Sciences A dimensionless number equal to the ratio of water velocity to the speed of a gravity wave, used to assess whether flow in an open channel is critical, tranquil, or shooting. If the Froude number is less than 1, flow is said to be subcritical or slow; if Fr = 1, flow is critical; and if Fr is greater than 1, flow is fast or supercritical. Geography The ratio of the velocity (v) of a river to its celerity where celerity is the product of the acceleration due to gravity (g) and the mean depth of flow (d). The Froude number (Fe) is calculated from the equation: $F_{e} = \frac{v}{\sqrt{g d}}$ Where F_e is less than 1, deeper flow is tranquil. Where F_e exceeds 1, the flow is turbulent. See Lewin and Brewer (2001) Geomorph. 40 on Froude numbers and channel patterns.
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