CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Wiki > Power-law viscosity law

Power-law viscosity law

From CFD-Wiki

(Difference between revisions)
Jump to: navigation, search
Jola (Talk | contribs)
(New page: A power-law can be used as an approximation of the viscosity of dilute gases. For dilute gases at moderate temperatures, this form is slightly less accurate than Sutherland's law. The ...)
Newer edit →

Revision as of 21:17, 17 May 2007

A power-law can be used as an approximation of the viscosity of dilute gases. For dilute gases at moderate temperatures, this form is slightly less accurate than Sutherland's law. The power-law viscosity law can be written as:

\mu = BT^n

Where \mu is the viscosity in kg/m-s, T is the static temperature in K, and B is a dimensional coefficient. For air at moderate temperatures and pressures B = 4.093 \times 10^{-7}, and n = 2/3.

The power-law viscosity law can also be written as:

\mu = \mu_{ref} \left(\frac{T}{T_{ref}}\right)^n

Where \mu is the viscosity in kg/m-s, T is the static temperature in K, T_{ref} is a reference value in K, \mu_{ref} is a reference value in kg/m-s. For air at moderate temperatures and pressures, \mu_{ref} = 1.716\times 10^{-5} kg/m-s, T_{ref} = 273 K, and n = 2/3.

Note that there exists a different power-law for non-Newtonian fluids!

My wiki