Ohnesorge number

From Wikipedia, the free encyclopedia

The Ohnesorge number, Oh , is a dimensionless number that relates the viscous and surface tension force.

It is defined as: Oh = \frac{ \mu}{ \sqrt{\rho \sigma L }}

Where

  • μ is the liquid viscosity
  • ρ is the liquid density
  • σ is the surface tension
  • L is the characteristic length scale (typically- drop diameter)

[edit] Applications

The Ohnesorge number for a 3 mm diameter rain drop is typically ~0.002. Larger Ohnesorge numbers indicate a more influence of the viscosity .

This is often used to relate to free surface fluid dynamics such as dispersion of liquids in gases and in spray technology.[1] [2]

[edit] References

  1. ^ Lefebvre, Arthur Henry (1989), Atomization and Sprays, New York and Washington, D.C.: Hemisphere Publishing Corp., ISBN 978-0-89116-603-0, OCLC 18560155 
  2. ^ Ohnesorge, W (1936). "Formation of drops by nozzles and the breakup of liquid jets". Zeitschrift für Angewandte Mathematik und Mechanik (ZAMM) [Applied Mathematics and Mechanics] 16: 355–358. Berlin: Akademie Verlag. 

[edit] See also

  • Laplace number - There is an inverse relationship, Oh = 1/\sqrt{La}, between the Laplace number and the Ohnesorge number. It is more historically correct to use the Ohnesorge number, but often mathematically neater to use the Laplace number.
v • d • e
Dimensionless numbers in fluid dynamics
Archimedes • Atwood • Bagnold • Biot • Bond • Brinkman • Capillary • Cauchy • Damköhler • Dean • Deborah • Eckert • Ekman • Eötvös • Euler • Froude • Galilei • Grashof • ‎Görtler • Hagen • Knudsen • Laplace • Lewis • Mach • Magnetic Reynolds • Marangoni • Morton • Nusselt • Ohnesorge • Péclet • Prandtl • Rayleigh • Reynolds • Richardson • Roshko • Rossby • Ruark • Schmidt • Sherwood • Stanton • Stokes • Strouhal • Suratman • Taylor • Weber • Weissenberg • Womersley
This fluid dynamics-related article is a stub. You can help Wikipedia by expanding it.