Galileo number

Physical key figure
Surname	Galileo number
Formula symbol	${\displaystyle {\mathit {Ga}}}$
dimension	dimensionless
definition	${\displaystyle {\mathit {Ga}}={\frac {g\,L^{3}}{\nu ^{2}}}}$
${\displaystyle g}$ Acceleration due to gravity ${\displaystyle L}$ characteristic length ${\displaystyle \nu }$ kinematic viscosity
Named after	Galileo Galilei
scope of application	Film flows under the influence of gravity

The Galilei number  is a dimensionless number from the field of fluid mechanics  named after Galileo Galilei (1564–1642) . It characterizes the relationship between gravitational and internal frictional forces in moving fluids and is defined as: ${\displaystyle {\mathit {Ga}}}$

${\displaystyle {\mathit {Ga}}={\frac {g\,L^{3}}{\nu ^{2}}}}$

With

• ${\displaystyle g}$: Gravitational acceleration
• ${\displaystyle L}$: characteristic length
• ${\displaystyle \nu }$: characteristic, kinematic viscosity .

It is also the quotient of the square of the Reynolds number and the Froude number : ${\displaystyle {\mathit {Re}}}$ ${\displaystyle {\mathit {Fr}}}$

${\displaystyle {\mathit {Ga}}={\frac {{\mathit {Re}}^{2}}{\mathit {Fr}}}}$

The Galilei number is used in thin-film physics and process engineering (e.g. in packed columns ) to describe the flow condition of liquid - film flows over wetting walls when the film flow is influenced by gravity . The film length is used as the characteristic length.

swell

• VDI (Ed.): VDI-Wärmeatlas . 5th, expanded edition. VDI Verlag, Düsseldorf 1988, page Bc 1, ISBN 3-18-400850-9 .
• Walter Wagner: heat transfer. Basics . 5th, revised edition. Verlag Vogel Fachbuch, Würzburg 1998, page 119, ISBN 3-8023-1703-3 .

Individual evidence

1. ^ Josef Kunes: Dimensionless Physical Quantities in Science and Engineering . Elsevier, 2012, ISBN 0-12-391458-2 , pp. 123 ( limited preview in Google Book search).
2. ↑ Alfons Mersmann, Matthias Kind, Johann Stichlmair: Thermal process engineering: Fundamentals and methods . Springer-Verlag, 2005, ISBN 3-540-28052-9 , pp. 198 ( limited preview in Google Book Search).