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Deborah number
From Wikipedia, the free encyclopedia
The Deborah number is a dimensionless number, used in rheology to characterize how "fluid" a material is. Even some apparent solids "flow" if they are observed long enough; the origin of the name is the line "The mountains flowed before the Lord" in a song by prophetess Deborah recorded in the Bible (Judges 5:5).
Formally, the Deborah number is defined as the ratio of a relaxation time, characterizing the intrinsic fluidity of a material, and the characteristic time scale of an experiment (or a computer simulation) probing the response of the material. The smaller the Deborah number, the more fluid the material appears.
The equation is thus:
Where tc refers to the characteristic timeframe and tp refers to the timeframe of the phenomenon.
- Marcus Reiner on the Deborah number.
| Dimensionless numbers in fluid dynamics |
|---|
| Archimedes • Bagnold • Bond • Brinkman • Capillary • Damköhler • Deborah • Eckert • Ekman • Euler • Froude • Galilei • Grashof • Hagen • Knudsen • Laplace • Lewis • Mach • Marangoni • Nusselt • Ohnesorge • Péclet • Prandtl • Rayleigh • Reynolds • Richardson • Rossby • Schmidt • Sherwood • Stanton • Stokes • Strouhal • Weber • Weissenberg • Womersley |