- Applications
- See also
- References
The Ohnesorge number (Oh) is a dimensionless number that relates the viscous forces to inertial and surface tension forces. The number was defined by Wolfgang von Ohnesorge in his 1936 doctoral thesis.[1]
It is defined as:
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)
- Re is the Reynolds number
- We is the Weber number
Applications
The Ohnesorge number for a 3 mm diameter rain drop is typically ~0.002. Larger Ohnesorge numbers indicate a greater 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.[2][3]
In inkjet printing, liquids whose Ohnesorge number is less than 1 and greater than 0.1 are jettable (1
See also
- Laplace number - There is an inverse relationship,
, 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.
References
1. ^1 {{cite journal | first = Gareth H. | last = McKinley | last2 = Renardy | first2 = Michael | year = 2011 | title = Wolfgang von Ohnesorge | journal = Physics of Fluids | volume = 23 | page = 127101 | doi = 10.1063/1.3663616 |bibcode = 2011PhFl...23l7101M }}
2. ^{{Cite book | author = Lefebvre, Arthur Henry | title = Atomization and Sprays | publisher = Hemisphere Publishing Corp. | location = New York and Washington, D.C. | year = 1989 | isbn = 978-0-89116-603-0 | oclc = 18560155 }}
3. ^{{cite journal | last = Ohnesorge | first = W | title = Formation of drops by nozzles and the breakup of liquid jets | journal = Journal of Applied Mathematics and Mechanics | volume = 16 | pages = 355–358 | date = 1936 }}
4. ^{{cite journal|last1=Derby|first1=Brian|title=Inkjet Printing of Functional and Structural Materials: Fluid Property Requirements, Feature Stability, and Resolution|journal=Annual Review of Materials Research|volume=40|issue=1|year=2010|pages=395–414|issn=1531-7331|doi=10.1146/annurev-matsci-070909-104502|bibcode=2010AnRMS..40..395D}}
{{NonDimFluMech}}{{fluiddynamics-stub}}2. ^{{Cite book | author = Lefebvre, Arthur Henry | title = Atomization and Sprays | publisher = Hemisphere Publishing Corp. | location = New York and Washington, D.C. | year = 1989 | isbn = 978-0-89116-603-0 | oclc = 18560155 }}
3. ^{{cite journal | last = Ohnesorge | first = W | title = Formation of drops by nozzles and the breakup of liquid jets | journal = Journal of Applied Mathematics and Mechanics | volume = 16 | pages = 355–358 | date = 1936 }}
4. ^{{cite journal|last1=Derby|first1=Brian|title=Inkjet Printing of Functional and Structural Materials: Fluid Property Requirements, Feature Stability, and Resolution|journal=Annual Review of Materials Research|volume=40|issue=1|year=2010|pages=395–414|issn=1531-7331|doi=10.1146/annurev-matsci-070909-104502|bibcode=2010AnRMS..40..395D}}
2 : Dimensionless numbers of fluid mechanics|Fluid dynamics
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