Generalized Newtonian fluid

A generalized Newtonian fluid is an idealized fluid for which the shear stress is a function of shear rate at the particular time, but not dependent upon the history of deformation. Despite this type of fluid is non-Newtonian (i.e. non-linear) in nature, its constitutive equation is a generalised form of the Newtonian fluid. Generalised Newtonian fluids satisfy the following rheological equation:

$\tau = \mu_{\operatorname{eff}}( \dot{\gamma} ) \dot{\gamma}$

where $\tau$ is the shear stress, and $\dot{\gamma}$ the shear rate. The quantity $\mu_{\operatorname{eff}}$ represents an apparent or effective viscosity as a function of the shear rate.

The most commonly used types of generalized Newtonian fluids are:^[1]

• Power-law fluid
• Cross fluid
• Carreau fluid
• Second-order fluid

See also

• Navier–Stokes equations

References

1. ↑ Kennedy, Peter (1995). Flow analysis of injection molds. Munich u.a.: Hanser u.a. ISBN 1-56990-181-3.