Carreau fluid is a type of generalized Newtonian fluid where viscosity, , depends upon the shear rate, , by the following equation:

Where: , , and are material coefficients.

= viscosity at zero shear rate (Pa.s)

= viscosity at infinite shear rate (Pa.s)

= relaxation time (s)

= power index


At low shear rate () a Carreau fluid behaves as a Newtonian fluid with viscosity . At intermediate shear rates (), a Carreau fluid behaves as a Power-law fluid. At high shear rate, which depends on the power index and the infinite shear-rate viscosity , a Carreau fluid behaves as a Newtonian fluid again with viscosity .

The model was first proposed by Pierre Carreau.


This article uses material from the Wikipedia article Carreau fluid, which is released under the Creative Commons Attribution-Share-Alike License 3.0.