In
fluid dynamics, the Galilei number (Ga), sometimes also referred to as Galileo number (see discussion), is a
dimensionless number
A dimensionless quantity (also known as a bare quantity, pure quantity, or scalar quantity as well as quantity of dimension one) is a quantity to which no physical dimension is assigned, with a corresponding SI unit of measurement of one (or 1) ...
named after Italian scientist
Galileo Galilei
Galileo di Vincenzo Bonaiuti de' Galilei (15 February 1564 – 8 January 1642) was an Italian astronomer, physicist and engineer, sometimes described as a polymath. Commonly referred to as Galileo, his name was pronounced (, ). He wa ...
(1564-1642).
It may be regarded as proportional to gravity forces divided by viscous forces. The Galilei number is used in viscous flow and thermal expansion calculations, for example to describe fluid film flow over walls. These flows apply to condensers or chemical columns.
:
* ''g'':
gravitational acceleration
In physics, gravitational acceleration is the acceleration of an object in free fall within a vacuum (and thus without experiencing drag). This is the steady gain in speed caused exclusively by the force of gravitational attraction. All bodi ...
, (
SI units:
m/
s2)
* ''L'': characteristic length, (
SI units: m)
* ''ν'': characteristic
kinematic viscosity
The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water.
Viscosity quantifies the int ...
, (
SI units: m
2/s)
See also
*
Archimedes number
In viscous fluid dynamics, the Archimedes number (Ar), is a dimensionless number used to determine the motion of fluids due to density differences, named after the ancient Greek scientist and mathematician Archimedes.
It is the ratio of gravit ...
References
*VDI-Wärmeatlas; 5., extended Edition; VDI Verlag Düsseldorf; 1988; page Bc 1 (German)
*W. Wagner; Wärmeübertragung; 5., revised Edition; Vogel Fachbuch; 1998; page 119 (German)
External links
Website referring to the Galileo number with calculatorTable of dimensionless numbers (German)Table of dimensionless numbers (German)
{{NonDimFluMech
Dimensionless numbers of fluid mechanics
Fluid dynamics