Sutherland's law
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:<math>C_1 = \frac{\mu_{ref}}{T_{ref}^{3/2}}(T_{ref} + S)</math> | :<math>C_1 = \frac{\mu_{ref}}{T_{ref}^{3/2}}(T_{ref} + S)</math> | ||
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|+ Sutherland's law coefficients: | |+ Sutherland's law coefficients: | ||
! Gas !! <math>\mu_0 [\frac{kg}{m s}]</math> !! <math>T_0 [K]</math> !! <math>S [K]</math> !! <math>C_1 [\frac{kg}{m s K ^ {0.5}}]</math> | ! Gas !! <math>\mu_0 [\frac{kg}{m s}]</math> !! <math>T_0 [K]</math> !! <math>S [K]</math> !! <math>C_1 [\frac{kg}{m s K ^ {0.5}}]</math> |
Revision as of 17:20, 17 May 2007
In 1893 William Sutherland, an Australian physicist, published a relationship between the dynamic visocity, , and the absolute temperature, , of an ideal gas. This formula, often called Sutherland's law, is based on kinetic theory of ideal gases and an idealized intermolecular-force potential. Sutherland's law is still commonly used and most often gives fairly accurate results with an error less than a few percent over a wide range of temperatures. Sutherland's law can be expressed as:
- is a reference temperature.
- is the viscosity at the reference temperature
- S is the Sutherland temperature
Some authors instead express Sutherland's law in the following form:
Comparing the formulas above the constant can be written as:
Gas | ||||
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Air |
References
- Sutherland, W. (1893), "The viscosity of gases and molecular force", Philosophical Magazine, S. 5, 36, pp. 507-531 (1893).